Question 1. I have been examining my earth bonding and have found
that the earth connection between where the cable enters my house to
the other size of the main fuse is made from earth cable that is only
about 3mm thick at most and it is not insulated. Presumeably this is
fairly old. This is only a short length about 25cm. There is then a
copper covered cable that goes for about 6 metres to the meter. The
earth connection into the consumer unit and connected to the gas and
water is much more substantial and is insulated.

Is there any danger posed by the thin link around the main fuse? Should
I replace it?

Question 2. (see previous post) In my laundry/shower/toilet room there
is no earth bonding. I understand that I must link all the pipes
together. However my radiator is on the otherside of the room and I
don't want to rip up floor boards to fit the cable. Is it alright to
route this via my cellar back to where the cold water pipe enters the
room. This means that effectively the cable will be going around the
outside of the room. Do I have to put the connection in the laundry
room or can I make this in the cellar?

Thanks as always
Tim

.....further question. I am installing additional sockets in my kitchen.
As this is being replastered I intend to cover the cables with
capping/sheathing. If I use the galvanised type should this be earthed?

wrote in message

Question 1. I have been examining my earth bonding and have found
that the earth connection between where the cable enters my house to
the other size of the main fuse is made from earth cable that is only
about 3mm thick at most and it is not insulated. Presumeably this is
fairly old. This is only a short length about 25cm. There is then a
copper covered cable that goes for about 6 metres to the meter. The
earth connection into the consumer unit and connected to the gas and
water is much more substantial and is insulated.

From your bare description this sounds inadequate but for me to make
useful observations you need to provide clearer information about your
installation eg

approx age; if possible the earthing system (TT/TN-C-S/PME/TN-C are
the most likely).

A 'schematic' of your installation would help. eg something like

incoming mains - supplier's fuse - supply meter - main switch -
consumer unit (or fuse box) -house circuits

& any other boxes, indicating where the earth connects in & the
connection to your water/gas/oil pipes. Any indication of cable sizes
you can give would also help. Is there an earthing rod?

Much of the information (with diagrams) you want is in the IEE On-Site
Guide (checkout amazon &/or the IEE web site to purchase)



Is there any danger posed by the thin link around the main fuse? Should
I replace it?


If you can repost with above info will try to help.


Question 2. (see previous post) In my laundry/shower/toilet room there
is no earth bonding. I understand that I must link all the pipes
together.

that's right (see on-site guide)


However my radiator is on the otherside of the room and I
don't want to rip up floor boards to fit the cable. Is it alright to
route this via my cellar back to where the cold water pipe enters the
room. This means that effectively the cable will be going around the
outside of the room. Do I have to put the connection in the laundry
room or can I make this in the cellar?


SFAIUI the bonding cable does not have to be within the room, though
the clamp links to the metalwork do. Caution & ohms law suggest
Prudence would keep the cable route as short as possible. It must also
connect to the main house earth bonding (into the earth in a
convenient socket seems to be OK SFAIUI).

also from your other post

.....further question. I am installing additional sockets in my
kitchen.
As this is being replastered I intend to cover the cables with
capping/sheathing. If I use the galvanised type should this be
earthed?

FT&E PVC cable does not have to be covered with capping before
plastering. It can be clipped to the wall and simply plastered over
with the browning (undercoat) coat.

Capping (especially metal) provides some resistance to drawing pins
and the like but isn't foolproof. Don't confuse it with conduit which
usually comes in thick, nail resistant, tubes & is a diffeent kettle
of fish (with different cable rating tables applying).

Capping does not need earthing. Conduit may do.

You may only route cable in 150mm wide bands, vertically and
horizontally from a fitting (a switch, socket, light outlet etc) &
along vertical wall corners and the ceiling/top of wall corner. Note
routeing behind skirting boards doesn't normally meet these rules. If
you depart from these routes (eg run diagonally across the wall) then
the cable must be at least 50mm deep in the wall or run in earthed
conduit (not capping). Again, rules are in the on-site guide.

BTW what do you mean when you refer to 'sheathing'? The grey
(sometimes white) covering of FT&E cable is a sheath intended to
protect the red & black insulation covering the copper cores from
physical damage. If your reference to sheathing means you are not
intending to use FT&E cable but individual L, N & E cables then they
must be run in conduit. SFAIUI covering individual cables with
capping is insufficient protection.

HTH

(jim_in_sussex) wrote in message . com...
wrote in message

Question 1. I have been examining my earth bonding and have found
that the earth connection between where the cable enters my house to
the other size of the main fuse is made from earth cable that is only
about 3mm thick at most and it is not insulated. Presumeably this is
fairly old. This is only a short length about 25cm. There is then a
copper covered cable that goes for about 6 metres to the meter. The
earth connection into the consumer unit and connected to the gas and
water is much more substantial and is insulated.

From your bare description this sounds inadequate but for me to make
useful observations you need to provide clearer information about your
installation eg

approx age; if possible the earthing system (TT/TN-C-S/PME/TN-C are
the most likely).

The earthing is TNS. i.e. supplied via the armoured cable coming in
from the street. This looks to be at least 30 years old.


This goes into the suppliers fusebox. The other side of the fusebox is
a a copper covered cable which goes to the meter.

The armoured cable and this copper covered cable are joined on the
outside to continue the earth. This is done with uncovered stranded
cable of about 3mm diameter.

--- -------------
============= Fuse ================ ------- to meter
---| |-------------
|----earth link-----|

From the meter the tails are connected to the consumer unit. The earth
connection into the consumer unit is 10mm diameter insulated cable.
The earth is then connected to the gas and water pipes, again using
10mm insulated cable.

As far as I can tell this part appears to be fairly modern and appears
to be in line with my understanding of the regualations. It just seems
strange that the incoming earth by the fuse seems so inadequate.

Where does the supply companies responsibility end, is it at the fuse
or the meter. If at the meter, then I will be getting the electricity
company in to replace this.


A 'schematic' of your installation would help. eg something like

incoming mains - supplier's fuse - supply meter - main switch -
consumer unit (or fuse box) -house circuits

& any other boxes, indicating where the earth connects in & the
connection to your water/gas/oil pipes. Any indication of cable sizes
you can give would also help. Is there an earthing rod?

Much of the information (with diagrams) you want is in the IEE On-Site
Guide (checkout amazon &/or the IEE web site to purchase)



Is there any danger posed by the thin link around the main fuse? Should
I replace it?


If you can repost with above info will try to help.


Question 2. (see previous post) In my laundry/shower/toilet room there
is no earth bonding. I understand that I must link all the pipes
together.

that's right (see on-site guide)


However my radiator is on the otherside of the room and I
don't want to rip up floor boards to fit the cable. Is it alright to
route this via my cellar back to where the cold water pipe enters the
room. This means that effectively the cable will be going around the
outside of the room. Do I have to put the connection in the laundry
room or can I make this in the cellar?


SFAIUI the bonding cable does not have to be within the room, though
the clamp links to the metalwork do. Caution & ohms law suggest
Prudence would keep the cable route as short as possible. It must also
connect to the main house earth bonding (into the earth in a
convenient socket seems to be OK SFAIUI).

also from your other post

....further question. I am installing additional sockets in my
kitchen.
As this is being replastered I intend to cover the cables with
capping/sheathing. If I use the galvanised type should this be
earthed?

FT&E PVC cable does not have to be covered with capping before
plastering. It can be clipped to the wall and simply plastered over
with the browning (undercoat) coat.

Capping (especially metal) provides some resistance to drawing pins
and the like but isn't foolproof. Don't confuse it with conduit which
usually comes in thick, nail resistant, tubes & is a diffeent kettle
of fish (with different cable rating tables applying).

Capping does not need earthing. Conduit may do.

You may only route cable in 150mm wide bands, vertically and
horizontally from a fitting (a switch, socket, light outlet etc) &
along vertical wall corners and the ceiling/top of wall corner. Note
routeing behind skirting boards doesn't normally meet these rules. If
you depart from these routes (eg run diagonally across the wall) then
the cable must be at least 50mm deep in the wall or run in earthed
conduit (not capping). Again, rules are in the on-site guide.

BTW what do you mean when you refer to 'sheathing'? The grey
(sometimes white) covering of FT&E cable is a sheath intended to
protect the red & black insulation covering the copper cores from
physical damage. If your reference to sheathing means you are not
intending to use FT&E cable but individual L, N & E cables then they
must be run in conduit. SFAIUI covering individual cables with
capping is insufficient protection.

By sheathing I was referring to the capping. Thanks for the answer.

HTH

wrote in message

Question 1. I have been examining my earth bonding and have found
that the earth connection between where the cable enters my house to
the other size of the main fuse is made from earth cable that is only
about 3mm thick at most and it is not insulated.

3mm dia is 7sq mm - ie actually stock size 6mm sq??

SFAIUI it may not need insulation - would depend on risk of incidental
physical damage.

Presumeably this is
fairly old. This is only a short length about 25cm. There is then a
copper covered cable that goes for about 6 metres to the meter. The
earth connection into the consumer unit and connected to the gas and
water is much more substantial and is insulated.

From your bare description this sounds inadequate but for me to make
useful observations you need to provide clearer information about your
installation eg

approx age; if possible the earthing system (TT/TN-C-S/PME/TN-C are
the most likely).

The earthing is TNS. i.e. supplied via the armoured cable coming in
from the street. This looks to be at least 30 years old.


This goes into the suppliers fusebox. The other side of the fusebox is
a a copper covered cable which goes to the meter.

The armoured cable and this copper covered cable are joined on the
outside to continue the earth. This is done with uncovered stranded
cable of about 3mm diameter.

--- -------------
============= Fuse ================ ------- to meter
---| |-------------
|----earth link-----|


TFT but hard to be definite without seeing the set up.

Some thoughts:

loooking at the sizes specified in OSG table 10A (pg161) a 6mm sq
earth might be possible in a small sized supply (or possibly was
once?). On balance unlikely though, so:

*Perhaps* is the supply fuse box steel? It also sounds as if the
ongoing cables are MICC (mineral insulated copper covered) cables.

If so that may be a partial explanation. *If* it is steel & the
incomer is SWA then the box via the clamps at the inlet & outlet could
be providing earth continuity. The 6mmsq link being to reinforce the
earthing.


From the meter the tails are connected to the consumer unit. The earth
connection

sorry - not following you here precisely - earth connection from
where?

into the consumer unit is 10mm diameter insulated cable.

if you mean this is the main earthing conductor from the supply, then
it could well be a tad too small - 16mmsq being more normal.

do you mean 10mmsq?

The earth is then connected to the gas and water pipes, again using
10mm insulated cable.

If so that appears to be correct for usual sized domestic
installations (same OSG table).


As far as I can tell this part appears to be fairly modern and appears
to be in line with my understanding of the regualations. It just seems
strange that the incoming earth by the fuse seems so inadequate.

Where does the supply companies responsibility end, is it at the fuse
or the meter. If at the meter, then I will be getting the electricity
company in to replace this.

(a) so far as the supply (other than earth is concerned), at the point
the tails leave the elec co fuse or cut-out (if you have one), SFAIUI.
The tails are yours & you have to supply them if you have a new or
upgraded installation.

(b) earthing SFAIUI is the consumer's responsibility, but for certain
supply specs (PME/TN-C-S & TN-S) the elec co has (again, SFAIUI) to
supply an earth point. The rest is yours to worry about.

One way forward may be to check that everything your side of the
supplied earthing point is hanky-dory then ask the elec co to check
their earthing as it looks old/decayed/inadequate/some other sob
reason. Check if they'll charge first, though.



HTH

Thanks for the reply. I phoned up EDF our supplier and they agreed to
come out and inspect, which they did within 1 hour! I was very
impressed. The engineer agreed that the earth wire was a bit suspect,
but more importantly the MICC cable to the meter should now be replaced
as it was so old. They are now arranging to connect a brand new cable
all the way to the meter free of charge.

He also recommended that I upraded my consumer unit to include RCD
protection. Currently, I only have one RCD circuit which I installed,
that is used to supply my laundry/ shower room.

He reckons that for safety every circuit should be protected by an RCD
as in his 30+ years experience he has known about deaths caused by
people working on lighting circuits as well as mains circuits, but
acknowledges that this is not in the current regs. The main issue here
would be the cost of doing this via separate RCBOs instead of one RCB.

Has anyone got a view on this, apart from the cost I think it would be
a good idea. Maybe the only circuit I would not want on an RCB would be
my alarm and freezer. Or are there problems with triggering on
immersion heaters?

Finally, as I understand the regs kitchens should now definitely be
protected by an RCD. Do people run a separate ring or spur purely to
supply their freezer in the kitchen, presumeably this needs to be hard
wired to prevent people plugging things such as hedgecutters into it?

As they are coming to do the replacement in the next few days I was
thinking of connecting my CU to the meter via a 100A DP isolation
switch, as at the moment neither the meter or main fuse have seals on
them, which won't be the case after they have done the work on the
connection. Does anyone have any information on whether this is
allowed, it will make it a lot easier if I upgrade my CU (obviously
before 2005 and part p!)

In article ,
wrote:
He reckons that for safety every circuit should be protected by an RCD
as in his 30+ years experience he has known about deaths caused by
people working on lighting circuits as well as mains circuits, but
acknowledges that this is not in the current regs. The main issue here
would be the cost of doing this via separate RCBOs instead of one RCB.

Has anyone got a view on this, apart from the cost I think it would be
a good idea. Maybe the only circuit I would not want on an RCB would be
my alarm and freezer. Or are there problems with triggering on
immersion heaters?

Get a split load CU with more ways than you need. The spare ways can be
just blanked off. That will allow you to move things to the non protected
side if you have problems.

--
*I have plenty of talent and vision. I just don't care.

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
writes:
He reckons that for safety every circuit should be protected by an RCD
as in his 30+ years experience he has known about deaths caused by
people working on lighting circuits as well as mains circuits, but

The number of deaths caused by lighting circuits blacking out
is probably at least a couple of orders of magnitude greater.

acknowledges that this is not in the current regs. The main issue here
would be the cost of doing this via separate RCBOs instead of one RCB.

Has anyone got a view on this, apart from the cost I think it would be
a good idea. Maybe the only circuit I would not want on an RCB would be
my alarm and freezer. Or are there problems with triggering on
immersion heaters?

I would say that no lighting circuit should share an RCD with
anything else, and that they really don't merit an RCD each.
There are probably many ways you can use the money far more
effectively to improve your home safety.

Finally, as I understand the regs kitchens should now definitely be
protected by an RCD.

You understand incorrectly in tht respect.

Do people run a separate ring or spur purely to
supply their freezer in the kitchen, presumeably this needs to be hard
wired to prevent people plugging things such as hedgecutters into it?

I run a non-RCD protected circuit to a kitchen. I use it for
just about all the stationary appliances in the kitchen.
The sockets are positioned in places which are not convenient
for use for anything else, and plenty of accessible sockets
are provided on an RCD protected ring for portable appliance
(and outdoor use). I tend to earth-bond the area around the
sink along the same lines as required for bathrooms (although
not for kitchens), and that includes ensuring the earths of
the two socket outlet circuits are bonded nearby.

As they are coming to do the replacement in the next few days I was
thinking of connecting my CU to the meter via a 100A DP isolation
switch, as at the moment neither the meter or main fuse have seals on
them, which won't be the case after they have done the work on the
connection. Does anyone have any information on whether this is
allowed, it will make it a lot easier if I upgrade my CU (obviously
before 2005 and part p!)

It is allowed. They will fit it for free if you have the right
type of switch. Go to an electrical wholesalers and explain what
it's for, and they'll give you something suitable.

--
Andrew Gabriel

In message , Andrew Gabriel
writes
In article ,
writes:
He reckons that for safety every circuit should be protected by an RCD
as in his 30+ years experience he has known about deaths caused by
people working on lighting circuits as well as mains circuits, but

The number of deaths caused by lighting circuits blacking out
is probably at least a couple of orders of magnitude greater.


And what were these people doing 'working' on lighting circuits which
were still live anyway?
--
Chris French, Leeds

Not being careful enough, clearly, but his point was that an RCD would
always protect you. But as Andrew said, people are far more likely to
have an accident because of the lights not working!

On Tue, 14 Sep 2004 01:16:34 UTC, "Dave Plowman (News)"
wrote:

In article ,
chris French wrote:
And what were these people doing 'working' on lighting circuits which
were still live anyway?

Changing a bulb on a two way circuit springs to mind.

Falling through the ceiling while working on the lighting circuits in
the loft....!

--
Bob Eager
begin a new life...dump Windows!

wrote:
Not being careful enough, clearly, but his point was that an RCD would
always protect you. But as Andrew said, people are far more likely to
have an accident because of the lights not working!

An RCD will *not* "always protect you".

It will only reduce the severity of a shock you get if you get
some part of your body between live and earth. If you put your
finger across live and neutral (quite easy if doing something to
lights) then the RCD will do nothing at all for you.

Even if the shock is caused by you being between live and earth
the RCD only reduces the *electrical* effect to (hopefully)
sub-lethal levels. You will still get a jolt and if you are, for
example, on a ladder may fall off and injure yourself just as
badly as if the RCD had not been there.

RCDs are not a panacea.

--
Chris Green

In article , writes
wrote:
Not being careful enough, clearly, but his point was that an RCD would
always protect you. But as Andrew said, people are far more likely to
have an accident because of the lights not working!

An RCD will *not* "always protect you".

It will only reduce the severity of a shock you get if you get
some part of your body between live and earth. If you put your
finger across live and neutral (quite easy if doing something to
lights) then the RCD will do nothing at all for you.

Correct...

Even if the shock is caused by you being between live and earth
the RCD only reduces the *electrical* effect to (hopefully)
sub-lethal levels. You will still get a jolt and if you are, for
example, on a ladder may fall off and injure yourself just as
badly as if the RCD had not been there.

Beg to differ.. as someone who was glued to a ladder due to lack of an
RCD(.

And who had a similar event with an RCD and hardly noticed a thing)

RCDs are not a panacea.

No, but their much, much, better than nothing....


--
Tony Sayer

In article ,
wrote:
It will only reduce the severity of a shock you get if you get
some part of your body between live and earth. If you put your
finger across live and neutral (quite easy if doing something to
lights) then the RCD will do nothing at all for you.

Thought the time taken for the RCD to trip made this rather unlikely?

--
*Why is the man who invests all your money called a broker?

Dave Plowman London SW
To e-mail, change noise into sound.

tony sayer wrote:
Even if the shock is caused by you being between live and earth
the RCD only reduces the *electrical* effect to (hopefully)
sub-lethal levels. You will still get a jolt and if you are, for
example, on a ladder may fall off and injure yourself just as
badly as if the RCD had not been there.

Beg to differ.. as someone who was glued to a ladder due to lack of an
RCD(.

I really don't understand this on AC, I've never received a shock from
AC which has 'glued' me to anything and I've only ever heard anecdotal
evidence that this happens.

Presumably you became 'unglued' at some point or you wouldn't be here
to tell us about it! :-) Did you immediately try the same thing
with an RCD on the circuit and find that was alright?

--
Chris Green

"Dave Plowman (News)" wrote:
In article ,
wrote:
It will only reduce the severity of a shock you get if you get
some part of your body between live and earth. If you put your
finger across live and neutral (quite easy if doing something to
lights) then the RCD will do nothing at all for you.

Thought the time taken for the RCD to trip made this rather unlikely?

The RCD won't *ever* trip if you put your finger across live and
neutral, it dosn't trip on that sort of fault.

--
Chris Green

In article , writes
tony sayer wrote:
Even if the shock is caused by you being between live and earth
the RCD only reduces the *electrical* effect to (hopefully)
sub-lethal levels. You will still get a jolt and if you are, for
example, on a ladder may fall off and injure yourself just as
badly as if the RCD had not been there.

Beg to differ.. as someone who was glued to a ladder due to lack of an
RCD(.

I really don't understand this on AC, I've never received a shock from
AC which has 'glued' me to anything and I've only ever heard anecdotal
evidence that this happens.

No it does happen and although it was some 25 years ago I still remember
it very vividly!. It was from an electric drill metal cased in the one
hand, literally!, and to a metal ladder in soft solid soil in the other
hand making the earth connection. Apparently it was lead sheathed cable
where the earth connection had come undone at the dist board and there
was no direct connection but for the Capactive leakage in the house
wiring. Very painful and I couldn't move or call out, total paralysis(

Presumably you became 'unglued' at some point or you wouldn't be here
to tell us about it! :-) Did you immediately try the same thing
with an RCD on the circuit and find that was alright?


Fortunately I was working with someone who cottoned on too what was
happening, and he unplugged the drill. Apparently, he had a similar
thing before with the same type of drill and he was able to kick the
plug out of the socket. Thank god for the 1974 health and safety at work
act!, double insulation, and RCD's)

In those days RCD's were almost unheard of but had one been in place it
would have repeatedly tripped and shown up the "earth" fault. And no I'm
not going back there as it was a very long time ago, and I still shiver
whenever I go past there with what did happen, and how that might have
ended up!.

At the hospital the doctor said if it had gone on for much longer the
heart would have not worked properly etc, and that would have been that,
and I'd have been in permanent "earth" connection.....
--
Tony Sayer

In article , writes
"Dave Plowman (News)" wrote:
In article ,
wrote:
It will only reduce the severity of a shock you get if you get
some part of your body between live and earth. If you put your
finger across live and neutral (quite easy if doing something to
lights) then the RCD will do nothing at all for you.

Thought the time taken for the RCD to trip made this rather unlikely?

The RCD won't *ever* trip if you put your finger across live and
neutral, it dosn't trip on that sort of fault.


*Not strictly true, if you know how an RCD actually works. There will
still be "some" leakage current through your body that does not go back
via the neutral return so if that exceeds the RCD trip current, quite
likely, then out she goes!.....
--
Tony Sayer

I am coming round to the idea that I should replace my CU with a split
load type. However rewiring the kitchen to include a non rcd circuit
for the freezer, fridge and dishwasher is going to be a right pain.

Does the group have any views on whether having these on an rcd is
really going to be a problem due to tripping. If I am out of the house
on holiday for 2 weeks, I suppose there is a potential that the freezer
might turn off and ruin my food, but I would expect my insurance
company to pay out after the inevitable protracted dispute!

What are the items generally not rcd protected? assume this is lights
as mentioned previously, the alarm, garage (if separate protection
available), immersion heater due to potential earth leakage...are there
any others.

tony sayer wrote:
In article , writes
"Dave Plowman (News)" wrote:
In article ,
wrote:
It will only reduce the severity of a shock you get if you get
some part of your body between live and earth. If you put your
finger across live and neutral (quite easy if doing something to
lights) then the RCD will do nothing at all for you.

Thought the time taken for the RCD to trip made this rather unlikely?

The RCD won't *ever* trip if you put your finger across live and
neutral, it dosn't trip on that sort of fault.


*Not strictly true, if you know how an RCD actually works. There will
still be "some" leakage current through your body that does not go back
via the neutral return so if that exceeds the RCD trip current, quite
likely, then out she goes!.....

Standing on a ladder on a wooden (probably) floor the leakage through
your body to earth will be virtually non-existent. You'll probably
have shoes with rubber/plastic soles as well.

--
Chris Green

In article ,
wrote:
It will only reduce the severity of a shock you get if you get
some part of your body between live and earth. If you put your
finger across live and neutral (quite easy if doing something to
lights) then the RCD will do nothing at all for you.

Thought the time taken for the RCD to trip made this rather unlikely?

The RCD won't *ever* trip if you put your finger across live and
neutral, it dosn't trip on that sort of fault.

You miss the point. You'd have to bridge line and neutral within the trip
time of the RCD. That's what I was querying.

I'm not, of course, saying they are perfect. But perhaps better than
nothing?

--
*When the going gets tough, the tough take a coffee break *

Dave Plowman London SW
To e-mail, change noise into sound.

wrote in message
...
I am coming round to the idea that I should replace my CU with a split
load type. However rewiring the kitchen to include a non rcd circuit
for the freezer, fridge and dishwasher is going to be a right pain.

Does the group have any views on whether having these on an rcd is
really going to be a problem due to tripping. If I am out of the house
on holiday for 2 weeks, I suppose there is a potential that the freezer
might turn off and ruin my food, but I would expect my insurance
company to pay out after the inevitable protracted dispute!

What are the items generally not rcd protected? assume this is lights
as mentioned previously, the alarm, garage (if separate protection
available), immersion heater due to potential earth leakage...are there
any others.


I'm very much in favour of individual RCBOs rather than split units.

Advantages are that you know exactly which circuit is causing the problem,
and that might help track down errant devices.

Also, a fault caused by use of an appliance outside (those wires just keep
dangling in the way of the hedge trimmer...) won't mean that you have to
reset all the digital clocks in your house & any IT equipment doesn't have
to suffer the indignancy of a rude shut-down.

Disadvantages being the higher cost and sometimes a larger CU (RCBOs are
often double width, though singles are available).



--
Richard Sampson

mail me at
richard at olifant d-ot co do-t uk

In article ,
writes
I am coming round to the idea that I should replace my CU with a split
load type. However rewiring the kitchen to include a non rcd circuit
for the freezer, fridge and dishwasher is going to be a right pain.

Does the group have any views on whether having these on an rcd is
really going to be a problem due to tripping. If I am out of the house
on holiday for 2 weeks, I suppose there is a potential that the freezer
might turn off and ruin my food, but I would expect my insurance
company to pay out after the inevitable protracted dispute!

Isn't there some sort of alarm that dials up your mobile doggy bone and
tells you the good news?.

Or do like we do, never go away

What are the items generally not rcd protected? assume this is lights
as mentioned previously, the alarm, garage (if separate protection
available), immersion heater due to potential earth leakage...are there
any others.

In my humble opinion everything should be on RCD....
--
Tony Sayer

In article , writes
tony sayer wrote:
In article , writes
"Dave Plowman (News)" wrote:
In article ,
wrote:
It will only reduce the severity of a shock you get if you get
some part of your body between live and earth. If you put your
finger across live and neutral (quite easy if doing something to
lights) then the RCD will do nothing at all for you.

Thought the time taken for the RCD to trip made this rather unlikely?

The RCD won't *ever* trip if you put your finger across live and
neutral, it dosn't trip on that sort of fault.


*Not strictly true, if you know how an RCD actually works. There will
still be "some" leakage current through your body that does not go back
via the neutral return so if that exceeds the RCD trip current, quite
likely, then out she goes!.....

Standing on a ladder on a wooden (probably) floor the leakage through
your body to earth will be virtually non-existent. You'll probably
have shoes with rubber/plastic soles as well.


Don't you believe it!. Well if you do, then grab the mains in one hand
and note the results.

Usual disclaimer don't they this at home unless by doing so you'll help
the gene pool along.......
--
Tony Sayer

tony sayer wrote:
Standing on a ladder on a wooden (probably) floor the leakage through
your body to earth will be virtually non-existent. You'll probably
have shoes with rubber/plastic soles as well.


Don't you believe it!. Well if you do, then grab the mains in one hand
and note the results.

Usual disclaimer don't they this at home unless by doing so you'll help
the gene pool along.......

Have *you* actually done it? I've hung on to the output of a Van de
Graaf generator while simply standing on a piece of perspex and charged
myself up to hundreds of thousands of volts if not millions - not a
tingle, until someone walks to close to you.

In reality in the house you have to be touching something metallic or
standing on a wet (probably concrete) floor to get a shock. In
ordinary shoes on a carpet you will feel *nothing* if you touch live
mains with one finger (and, yes, I have done it occasionally when
working on something live). Mostly one gets a shock because *both*
hands are touching something conductive (and that's the worst for you
too as the electricity runs across your chest).

In workplaces where live working on benches is commonplace significant
shock prevention is provided by a vinyl floor covering and training
people to use only one hand.

--
Chris Green

In article , writes
tony sayer wrote:
Standing on a ladder on a wooden (probably) floor the leakage through
your body to earth will be virtually non-existent. You'll probably
have shoes with rubber/plastic soles as well.


Don't you believe it!. Well if you do, then grab the mains in one hand
and note the results.

Usual disclaimer don't they this at home unless by doing so you'll help
the gene pool along.......

Have *you* actually done it?

No...

I've hung on to the output of a Van de
Graaf generator while simply standing on a piece of perspex and charged
myself up to hundreds of thousands of volts if not millions - not a
tingle, until someone walks to close to you.

AC v DC ?...


In reality in the house you have to be touching something metallic or
standing on a wet (probably concrete) floor to get a shock.

I refer you to the above..

In
ordinary shoes on a carpet you will feel *nothing* if you touch live
mains with one finger (and, yes, I have done it occasionally when
working on something live).

So have I..

Mostly one gets a shock because *both*
hands are touching something conductive (and that's the worst for you
too as the electricity runs across your chest).

Yes, I have had first hand/s experience of that

In workplaces where live working on benches is commonplace significant
shock prevention is provided by a vinyl floor covering and training
people to use only one hand.

Good idea...
--
Tony Sayer

Dave Plowman (News) wrote:

You miss the point. You'd have to bridge line and neutral within the trip
time of the RCD. That's what I was querying.

Not if it's the N you touch first - there'd be naff-all current passing
through you given the negligible potential between N and local earth,
together with the much higher resistance which you present as a path to
earth/transformer-return as compared to the copper path it's got. Then
when you make contact with L (other side of the finger - possible
finger-cooking but little likelihood of death; other hand - definite
risk of fatality, hence the habit inculcated into generations of
sparkies of working with one hand at a time) you become an attractive
path for L-to-N current; and by far the greater part of the flow through
you will be on the L-to-N path, which doesn't do anything to trip the
RCD, rather than the L-to-E-via-shoes/clothes/whatever which the RCD is
sensitive to.

I'm not, of course, saying they are perfect. But perhaps better than
nothing?

Definitely better than nothing, but not a cure-all, and a possible
source of a "risk compensation" effect - "oh, it's OK to work live on
the electrics, I have a whole-house RCD"...

Stefek

"tony sayer" wrote
| The RCD won't *ever* trip if you put your finger across live and
| neutral, it dosn't trip on that sort of fault.
| *Not strictly true, if you know how an RCD actually works. There
| will still be "some" leakage current through your body that does
| not go back via the neutral return so if that exceeds the RCD
| trip current, quite likely, then out she goes!.....
| Standing on a ladder on a wooden (probably) floor the leakage
| through your body to earth will be virtually non-existent.
| You'll probably have shoes with rubber/plastic soles as well.
| Don't you believe it!. Well if you do, then grab the mains in one
| hand and note the results.

I have done exactly this in the past, standing on rubber-backed carpet tiles
on a dry suspended timber floor. I vibrated gently at 50Hz and the RCD did
not trip. This was not a glancing touch as I was holding the L wire
intending to put it into a replacement socket faceplate.[1]

| Usual disclaimer don't they this at home unless by doing so you'll
| help the gene pool along.......

Glad I can do my bit for the gene pool without being forced into the messy
business of procreation :-)

Owain

[1] I pulled out the fuse and checked the first socket. Dead. Checked the
second socket. Dead. How the f'k was I supposed to guess the third socket in
the lounge was on the garage circuit (garage being on opposite side of
house, as well).

In article , Owain owain41276@
stirlingcity.co.uk writes
"tony sayer" wrote
| The RCD won't *ever* trip if you put your finger across live and
| neutral, it dosn't trip on that sort of fault.
| *Not strictly true, if you know how an RCD actually works. There
| will still be "some" leakage current through your body that does
| not go back via the neutral return so if that exceeds the RCD
| trip current, quite likely, then out she goes!.....
| Standing on a ladder on a wooden (probably) floor the leakage
| through your body to earth will be virtually non-existent.
| You'll probably have shoes with rubber/plastic soles as well.
| Don't you believe it!. Well if you do, then grab the mains in one
| hand and note the results.

I have done exactly this in the past, standing on rubber-backed carpet tiles
on a dry suspended timber floor. I vibrated gently at 50Hz and the RCD did
not trip. This was not a glancing touch as I was holding the L wire
intending to put it into a replacement socket faceplate.[1]

Course some people conduct better then others;!....

| Usual disclaimer don't they this at home unless by doing so you'll
| help the gene pool along.......

Glad I can do my bit for the gene pool without being forced into the messy
business of procreation :-)

Theres a howler there somewhere....

Owain

[1] I pulled out the fuse and checked the first socket. Dead. Checked the
second socket. Dead. How the f'k was I supposed to guess the third socket in
the lounge was on the garage circuit (garage being on opposite side of
house, as well).


On three occasions over the years I've seen someone take apparently dead
wires in their hands and mutter "I suppose this *is* dead"?. Touch them
together, and you'll soon find out SEZ I

On each occasion there was a flash and loud bang!, very loud in the
first instance as it was a three phase supply.

Last time was in the belfry of Ely Cathedral where once had been a
mobile phone base station. The 'err "short circuit" took out most of the
lights as well as disrupting a service.

A bit of positive spin helped lots,

"ere look arch-bish-whatever guv" "just imagine if that little lot had
gone up by accident at night eh?"

"wouldn't have any where to pray now would yer?"

Seemed to earn a lot of brownie points

--
Tony Sayer

"tony sayer" wrote
| | Usual disclaimer don't they this at home unless by doing so
| | you'll help the gene pool along.......
| Glad I can do my bit for the gene pool without being forced
| into the messy business of procreation :-)
| Theres a howler there somewhere....

I am doing my best to avoid producing little howlers and continue to enjoy a
good night's sleep, no vomit in the carpets, and no need to buy a
people-carrier.

| Last time was in the belfry of Ely Cathedral where once had been a
| mobile phone base station. The 'err "short circuit" took out most
| of the lights as well as disrupting a service.

What's really fun is when there's no-one in the church office on a Sunday
and an incoming phone call rings round all the extensions before ending up
at the one hidden under the pulpit.

| A bit of positive spin helped lots,
| "ere look arch-bish-whatever guv" "just imagine if that little lot had
| gone up by accident at night eh?"
| "wouldn't have any where to pray now would yer?"

"You wouldn't get any better if Jesus himeself was here, he was a chippie
not a sparkie."

Owain

tony sayer wrote:

Thank god for the 1974 health and safety at work
act!, double insulation, and RCD's)

The 1989 Electricity at Work Regulations and regular inspection and
testing in particular.

In those days RCD's were almost unheard of but had one been in place it
would have repeatedly tripped and shown up the "earth" fault.

Errr, why would the RCD have tripped because of an open-circuit earth in
the wiring? (I.e. it wouldn't.)

--
Andy

tony sayer wrote:

Don't you believe it!. Well if you do, then grab the mains in one hand
and note the results.

In typical dry indoor conditions you will feel nothing, as Chris rightly
says. I've often demonstrated this to people, sometimes to their great
surprise. It provokes thought.

Don't try it outdoors though while standing on an aluminium ladder with
its feet in damp soil...

And don't try it if the frequency of the supply is a few orders of
magnitude higher than 50 Hz or you'll discover the meanings of "earthed
via a reactance" and "skin effect" at the same time.

--
Andy

In article ,
Owain wrote:
"You wouldn't get any better if Jesus himeself was here, he was a chippie
not a sparkie."

Seen on a roadside pulpit:-

Jesus was a carpenter. Come and join us.

--
*Nothing is foolproof to a sufficiently talented fool.

Dave Plowman London SW
To e-mail, change noise into sound.

In article , Andy Wade
writes
tony sayer wrote:

Thank god for the 1974 health and safety at work
act!, double insulation, and RCD's)

The 1989 Electricity at Work Regulations and regular inspection and
testing in particular.

Well the 1974 act was a good start, as up to that time the safety of
employees wasn't a particular concern of employers as my dad found out
one day when he went to adjust the height of a circular saw blade, and
discovered the hard way that it didn't have the expected guard blade
protecting its underside.

He said afterwards that he didn't feel a thing at the moment it happened
it was the shock of seeing four fingers missing that caused him to keel
over.....

In those days RCD's were almost unheard of but had one been in place it
would have repeatedly tripped and shown up the "earth" fault.

Errr, why would the RCD have tripped because of an open-circuit earth in
the wiring? (I.e. it wouldn't.)

Humm.... Well the earth had come off at the distribution board and the
whole house was wired with this lead sheathed cable. So presuming that
the lead sheathing was all bonded together then there would have been
quite a lot of Capactive leakage from the live to earth, as one could
assume that at some stage the un-earthed lead casing would be connected
to another earth in the house, via lets say something like an immersion
heater or similar appliance, so I reckon that their would have been
sufficient Capactive and an unknown amount of resistive leakage
sufficient to trip the RCD.

There was quite enough current there to prevent me from doing anything
about it, and FWIW I have very dry skin and my hands were very dry on
that day, so I reckon that a trip would have been taken out.
--
Tony Sayer

In article , Andy Wade
writes
tony sayer wrote:

Don't you believe it!. Well if you do, then grab the mains in one hand
and note the results.

In typical dry indoor conditions you will feel nothing, as Chris rightly
says. I've often demonstrated this to people, sometimes to their great
surprise. It provokes thought.

Depending on how moist your skin is. Mines very dry, scaly lizard like
according to the missus, whilst hers is rather wet most of the time and
No, she does have a dishwasher.....


Don't try it outdoors though while standing on an aluminium ladder with
its feet in damp soil...

No...

And don't try it if the frequency of the supply is a few orders of
magnitude higher than 50 Hz or you'll discover the meanings of "earthed
via a reactance" and "skin effect" at the same time.

Yes and working with RF a lot of the time this is a good way to test if
an aerial is radiating


--
Tony Sayer