There is a fault in the neutral of one of the cables going to my six way
fuse box. To find this fault I am likely to have to remove the fuse box
so that I can inspect the incoming cables and maybe replace one of them.

This makes me wonder whether I should replace the fuse box with a modern
consumer unit, probably 8 way.

Can anyone recommend a suitable unit. One of the problems that will
inevitably occur is that the house wiring cables will be to short. So
ideally I would like a unit that has all the terminals close to the
cable entry point would be a bonus.


--
Michael Chare

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

On Saturday, 13 August 2016 22:21:07 UTC+1, Michael Chare wrote:
There is a fault in the neutral of one of the cables going to my six way
fuse box. To find this fault I am likely to have to remove the fuse box
so that I can inspect the incoming cables and maybe replace one of them.

This makes me wonder whether I should replace the fuse box with a modern
consumer unit, probably 8 way.

Can anyone recommend a suitable unit. One of the problems that will
inevitably occur is that the house wiring cables will be to short. So
ideally I would like a unit that has all the terminals close to the
cable entry point would be a bonus.

Type of earthing? Metal or plastic? Cheap or deluxe? 2 RCDs or RCBOs?


NT

On 13/08/2016 23:08, wrote:

Metal or plastic?

No option there any more. Amendment 3, must be metal.

--
Andy

In article ,
writes:
On Saturday, 13 August 2016 22:21:07 UTC+1, Michael Chare wrote:
There is a fault in the neutral of one of the cables going to my six way
fuse box. To find this fault I am likely to have to remove the fuse box
so that I can inspect the incoming cables and maybe replace one of them.

This makes me wonder whether I should replace the fuse box with a modern
consumer unit, probably 8 way.

Can anyone recommend a suitable unit. One of the problems that will
inevitably occur is that the house wiring cables will be to short. So
ideally I would like a unit that has all the terminals close to the
cable entry point would be a bonus.

Type of earthing? Metal or plastic? Cheap or deluxe? 2 RCDs or RCBOs?

A new domestic one pretty much has to be metal now.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On 14/08/2016 00:05, Andy Wade wrote:
On 13/08/2016 23:08, wrote:

Metal or plastic?

No option there any more. Amendment 3, must be metal.


I think it says non flammable, but most manufacturers are using cheap
pressed steel.

Changing the consumer unit is, along with some bathroom stuff still
notifiable so don't DIY if you are selling soon.

On 13/08/2016 22:20, Michael Chare wrote:

There is a fault in the neutral of one of the cables going to my six way
fuse box. To find this fault I am likely to have to remove the fuse box
so that I can inspect the incoming cables and maybe replace one of them.

This makes me wonder whether I should replace the fuse box with a modern
consumer unit, probably 8 way.

Can anyone recommend a suitable unit.

Pick any of the well known brands and you should be fine. MK is nice but
can be pricey - although sometime you will find package deals for a CU
and a selection of MCBs that are not bad.

Hager have a good range of stuff, also good quality. Contactum is cheap
and "ok". I tend to avoid the wholesalers own brands since its not
always obvious what you are getting or what the spares availability will
be like.

One of the problems that will
inevitably occur is that the house wiring cables will be to short. So
ideally I would like a unit that has all the terminals close to the
cable entry point would be a bonus.

You are likely to find that all 8 way boxes have a very similar layout
and that is likely to be different from your current CU. So arm yourself
with some suitable lengths of wire, and decent quality crimps (+tool) so
that you can extend the ones you need to. (you can also het a bit of
wiggle room by choosing the ordering of the MCBs to suite the wire
lengths you have).

For more on brands, see:

http://wiki.diyfaq.org.uk/index.php/Consumer_unit

for changing one:

http://wiki.diyfaq.org.uk/index.php/..._consumer_unit


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

"Michael Chare" wrote in message
...


ideally I would like a unit that has all the terminals close to the cable
entry point would be a bonus.

You are not the only one:-)

Although you can often gain extra cable by moving the box up or down.on may
installs.

Screwfix had an offer on a BG populated RCBO CU last week - I believe it
had 8 ways and 6 RCBOs. They are not bad CUs. I cannot check that ATM as the
Screwfix site is down. All RCBOs on a small unit may help with the existing
cable lengths on the L and N but do be prepared to have to extend the
earths.

Whatever CU you buy (it will need to be metal if you are meeting the 3rd
amendment regs) then you can often forget about using the existing knockouts
and just jigsaw whatever entry points you need and then use grommet strip.
Depending on how the tailes enter the CU then a gland pack such as

https://www.tlc-direct.co.uk/Products/WKTKP40R32.html

is essential.


--
Adam

En el artículo , Michael Chare mUNDERSCOREn
escribió:

This makes me wonder whether I should replace the fuse box with a modern
consumer unit, probably 8 way.

Beware that doing this can show up faults, such as shared neutrals, that
don't affect fused CUs. They can result in an RCD that trips and won't
reset.

--
(\_/)
(='.'=) systemd: the Linux version of Windows 10
(")_(")

On 14/08/2016 05:22, John Rumm wrote:
On 13/08/2016 22:20, Michael Chare wrote:

There is a fault in the neutral of one of the cables going to my six way
fuse box. To find this fault I am likely to have to remove the fuse box
so that I can inspect the incoming cables and maybe replace one of them.

This makes me wonder whether I should replace the fuse box with a modern
consumer unit, probably 8 way.

Can anyone recommend a suitable unit.

Pick any of the well known brands and you should be fine. MK is nice but
can be pricey - although sometime you will find package deals for a CU
and a selection of MCBs that are not bad.

Hager have a good range of stuff, also good quality. Contactum is cheap
and "ok". I tend to avoid the wholesalers own brands since its not
always obvious what you are getting or what the spares availability will
be like.

One of the problems that will
inevitably occur is that the house wiring cables will be to short. So
ideally I would like a unit that has all the terminals close to the
cable entry point would be a bonus.

You are likely to find that all 8 way boxes have a very similar layout
and that is likely to be different from your current CU. So arm yourself
with some suitable lengths of wire, and decent quality crimps (+tool) so
that you can extend the ones you need to. (you can also het a bit of
wiggle room by choosing the ordering of the MCBs to suite the wire
lengths you have).

Thanks, I just bought a Screwfix crimp tool to mend my hob!

Would these be suitable crimps:

http://www.ebay.co.uk/itm/100-X-Asso...AOSw3KFWgil T


Any need for additional insulation such as tape and/or heat shrink?

Are RCBOs a good idea?


--
Michael Chare

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

But of course nobody bothers anyhow, from what I've heard.
If he has to extend the cables he is also going to need some certified
connection system as well. I know its done as someone I visit in a block ogf
flats has the wires going into some form of connection block in a box and
new cables emerge the other side.
Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"dennis@home" wrote in message
web.com...
On 14/08/2016 00:05, Andy Wade wrote:
On 13/08/2016 23:08, wrote:

Metal or plastic?

No option there any more. Amendment 3, must be metal.


I think it says non flammable, but most manufacturers are using cheap
pressed steel.

Changing the consumer unit is, along with some bathroom stuff still
notifiable so don't DIY if you are selling soon.

On Sunday, 14 August 2016 09:18:05 UTC+1, Michael Chare wrote:
Would these be suitable crimps:
http://www.ebay.co.uk/itm/100-X-Asso...AOSw3KFWgil T

I wouldn't buy crimps from China. The last lot I bought from B&Q [1] were so soft I could deform them with finger pressure.

Owain


[1] I know, but I only wanted 10 and it was a bit an emergency.

In article ,
Michael Chare wrote:
There is a fault in the neutral of one of the cables going to my six way
fuse box. To find this fault I am likely to have to remove the fuse box
so that I can inspect the incoming cables and maybe replace one of them.

There is generally only one incoming neutral to a CU. All the others are
outgoing.

And any fault is far more likely to be elsewhere in the house - unless
work has recently been carried out on the CU.

--
*Why is a boxing ring square?

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

In article ,
John Rumm wrote:
You are likely to find that all 8 way boxes have a very similar layout
and that is likely to be different from your current CU. So arm yourself
with some suitable lengths of wire, and decent quality crimps (+tool) so
that you can extend the ones you need to. (you can also het a bit of
wiggle room by choosing the ordering of the MCBs to suite the wire
lengths you have).

Is there a need to use a crimp to extend a cable within a CU? After all it
will remain accessible, in terms of the regs. And I've seen more badly
made crimps than I'd like.

--
*If tennis elbow is painful, imagine suffering with tennis balls *

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

On 14/08/2016 09:17, Michael Chare wrote:
On 14/08/2016 05:22, John Rumm wrote:

You are likely to find that all 8 way boxes have a very similar layout
and that is likely to be different from your current CU. So arm yourself
with some suitable lengths of wire, and decent quality crimps (+tool) so
that you can extend the ones you need to. (you can also het a bit of
wiggle room by choosing the ordering of the MCBs to suite the wire
lengths you have).

Thanks, I just bought a Screwfix crimp tool to mend my hob!

Would these be suitable crimps:

http://www.ebay.co.uk/itm/100-X-Asso...AOSw3KFWgil T

They look like the right kind, however for this application I would play
safe and order something branded from CPC

Any need for additional insulation such as tape and/or heat shrink?

Not when extending individual wires inside the CU - only if you are
crimping cables outside.

Are RCBOs a good idea?

Yes. All RCBO setups are a top end solution - but it will cost more. It
gives the best levels of RCD discrimination available. (i.e. the effect
of a fault will be limited to the single circuit on which it occurs)

You may find a "high integrity" CU is a good compromise - that's one
where it has at least a couple of banks of MCBs with their own RCD, but
them also a couple of additional non RCD ways that you can fit RCBOs in.
So you can stick circuits with high leakage risk on their own RCBO, but
still lump together low risk circuits on shared RCDs.



--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 14/08/2016 11:45, Dave Plowman (News) wrote:
In article ,
John Rumm wrote:
You are likely to find that all 8 way boxes have a very similar layout
and that is likely to be different from your current CU. So arm yourself
with some suitable lengths of wire, and decent quality crimps (+tool) so
that you can extend the ones you need to. (you can also het a bit of
wiggle room by choosing the ordering of the MCBs to suite the wire
lengths you have).

Is there a need to use a crimp to extend a cable within a CU?

You can use chockie block if you prefer (or Wagos etc). The only real
advantage of crimps is they are slim and easy to thread through a rats
nest of wires if needs be.

After all it
will remain accessible, in terms of the regs. And I've seen more badly
made crimps than I'd like.

Yup, then again, I have met rather too many chock block terminals made
of cheese also!

I think I would probable go for Crimp, Wago, then Chock block in that
order of preference.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

In article ,
John Rumm wrote:
Is there a need to use a crimp to extend a cable within a CU?

You can use chockie block if you prefer (or Wagos etc). The only real
advantage of crimps is they are slim and easy to thread through a rats
nest of wires if needs be.

After all it
will remain accessible, in terms of the regs. And I've seen more badly
made crimps than I'd like.

Yup, then again, I have met rather too many chock block terminals made
of cheese also!

But I'd guess less common than cheap crimps and an even worse crimp tool.
Before any finger trouble.

I'd be inclined to use a decent chocolate block connector large enough for
the wires to overlap so both screws bite on both wires. Tighten till it
groans using the correct size screwdriver, and insulate with heatshrink.
That's what I did when fitting my replacement CU for the few wires which
wouldn't reach - if they couldn't easily be replaced. And I've not had any
problems.

I think I would probable go for Crimp, Wago, then Chock block in that
order of preference.

I personally hate those pre-insulated Red Blue and Yellow terminals -
especially bought from an unknown source. They may be just about
acceptable where the wire size is a tight fit, but when at the other end
of the stated sizes, give an extremely poor crimp. To see what I mean do a
trial one then carefully cut off the insulation. It looks terrible. Simply
squashed like you could do with pliers. Not a proper crimp at all - to me.
Of course like all domestic wiring it may never get near its stated
maximum load. But I'd not trust it for a circuit which does.

--
*Money isn't everything, but it sure keeps the kids in touch.

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

On 14/08/2016 09:00, Mike Tomlinson wrote:
[...]
Beware that doing this can show up faults, such as shared neutrals, that
don't affect fused CUs. They can result in an RCD that trips and won't
reset.

You're supposed to test and assess each circuit before connecting it to
the new CU.

This is a useful guide:
http://www.electricalsafetyfirst.org...1-Issue-3-.pdf

--
Andy

On Sun, 14 Aug 2016 12:45:23 +0100, John Rumm wrote:
snip

Are RCBOs a good idea?

Yes. All RCBO setups are a top end solution - but it will cost more. It
gives the best levels of RCD discrimination available. (i.e. the effect
of a fault will be limited to the single circuit on which it occurs)
snip

+1 for the RCBO; the extra up front cost may well save you loads of aggro
down stream.

Earth/neutral trips were the bane of my life, before I discovered RCBOs!

[Major rewire may have helped, of course.]

Cheers

Dave R

--
Windows 8.1 on PCSpecialist box

I'd be inclined to use a decent chocolate block connector large enough for
the wires to overlap so both screws bite on both wires.

For the record, that's the technique I always adopt with chock-block,
but I've never seen it done by a professional, or inside a
manufactured appliance.


--

Graham.

%Profound_observation%

On Sunday, 14 August 2016 14:34:31 UTC+1, Graham. wrote:
I'd be inclined to use a decent chocolate block connector large enough for
the wires to overlap so both screws bite on both wires.

For the record, that's the technique I always adopt with chock-block,
but I've never seen it done by a professional, or inside a
manufactured appliance.

I always do that when practical. Much better reliability & safety. Plus in situations where it's permissible you can also ignore the connector's current rating if you've got 2 copper cables pressed well against each other - most of the current bypasses the chocblock. That does not include house wiring of course.

For the record one can overtighten these things. Go too far and the cable ends become flat thin weak things that fracture readily.


NT

On Sun, 14 Aug 2016 11:42:31 +0100, "Dave Plowman (News)"
wrote:

In article ,
Michael Chare wrote:
There is a fault in the neutral of one of the cables going to my six way
fuse box. To find this fault I am likely to have to remove the fuse box
so that I can inspect the incoming cables and maybe replace one of them.

There is generally only one incoming neutral to a CU. All the others are
outgoing.

And any fault is far more likely to be elsewhere in the house - unless
work has recently been carried out on the CU.

I suspect he might not be using the term "incoming cables" in the
strct sence that you would use it.

After all, we would say "cable entry point" for all cables rather than
"cable exit"

Apart from which, AC swings both ways ;-)



--

Graham.

%Profound_observation%

Graham. pretended :
I'd be inclined to use a decent chocolate block connector large enough for
the wires to overlap so both screws bite on both wires.

For the record, that's the technique I always adopt with chock-block,
but I've never seen it done by a professional, or inside a
manufactured appliance.

+1..

On 14/08/2016 13:24, Dave Plowman (News) wrote:

I personally hate those pre-insulated Red Blue and Yellow terminals -
especially bought from an unknown source. They may be just about
acceptable where the wire size is a tight fit, but when at the other end
of the stated sizes, give an extremely poor crimp. To see what I mean do a
trial one then carefully cut off the insulation. It looks terrible. Simply
squashed like you could do with pliers. Not a proper crimp at all - to me.
Of course like all domestic wiring it may never get near its stated
maximum load. But I'd not trust it for a circuit which does.


I'm not sure I follow you: while such a crimp doesn't usually make
contact with the whole circumference of the cable , when made with a
ratchet crimper do they really give a smaller area of contact than in a
typical (eg choc strip) screwed connector?

--
Robin

"Dave Plowman (News)" wrote in message
...
In article ,


That's what I did when fitting my replacement CU for the few wires which
wouldn't reach - if they couldn't easily be replaced. And I've not had any
problems.


And there is nothing wrong with doing that.


--
Adam

In article ,
Michael Chare writes:
There is a fault in the neutral of one of the cables going to my six way
fuse box. To find this fault I am likely to have to remove the fuse box
so that I can inspect the incoming cables and maybe replace one of them.

This makes me wonder whether I should replace the fuse box with a modern
consumer unit, probably 8 way.

Can anyone recommend a suitable unit. One of the problems that will
inevitably occur is that the house wiring cables will be to short. So
ideally I would like a unit that has all the terminals close to the
cable entry point would be a bonus.

I recently used one of the new Wylex all metal CU's, and was happy
with it (using all RCBO's - don't look at the split load version).
Amendment 3 version has metal hinged cover and metal fuseway banks.

This was a different solution many years ago to replacing my CU
where the wires were not long enough (just predated brown and blue).

http://www.cucumber.demon.co.uk/cu1.jpg
http://www.cucumber.demon.co.uk/cu2.jpg

BTW, that's an industrial CU which gives you bags of space inside,
although I don't think that MEM/Eaton range is manufactured anymore.
If you use those DIN rail screw terminals, I would suggest getting
one size bigger than the total crossectional area when more than one
conductor is going into a terminal, as they don't have any spare
space over the stated size.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

In article ,
Robin wrote:
I'm not sure I follow you: while such a crimp doesn't usually make
contact with the whole circumference of the cable , when made with a
ratchet crimper do they really give a smaller area of contact than in a
typical (eg choc strip) screwed connector?

My whole point is the metal part doesn't get crimped round the entire
diameter of the cable because the insulation has some give to it. And more
so when the wire is at the small end of the range the crimp says it can
take. With a decent screw connection, the screw is nearly the width of the
hole, so properly tightened will give a pretty near all round contact.
Obviously if you choose the correct size connector strip.

A decent crimp *is* the best method. But those crimps often ain't decent.

--
*Never underestimate the power of stupid people in large groups.

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

On 14/08/2016 09:00, Mike Tomlinson wrote:
En el artículo , Michael Chare mUNDERSCOREn
escribió:

This makes me wonder whether I should replace the fuse box with a modern
consumer unit, probably 8 way.

Beware that doing this can show up faults, such as shared neutrals, that
don't affect fused CUs. They can result in an RCD that trips and won't
reset.


The original wiring in this bungalow we recently acquired was done quite
neatly, but unfortunately the property has been modified.

I wanted to remove a 13 amp socket to make it easier to put on wall
paper so I thought I could just pull out the appropriate fuse.

I plugged a lamp into the socket and removed each fuse in turn. The lamp
never went out!


--
Michael Chare

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

On 14/08/2016 14:55, Graham. wrote:
On Sun, 14 Aug 2016 11:42:31 +0100, "Dave Plowman (News)"
wrote:

In article ,
Michael Chare wrote:
There is a fault in the neutral of one of the cables going to my six way
fuse box. To find this fault I am likely to have to remove the fuse box
so that I can inspect the incoming cables and maybe replace one of them.

There is generally only one incoming neutral to a CU. All the others are
outgoing.

And any fault is far more likely to be elsewhere in the house - unless
work has recently been carried out on the CU.

I suspect he might not be using the term "incoming cables" in the
strct sence that you would use it.

After all, we would say "cable entry point" for all cables rather than
"cable exit"

Apart from which, AC swings both ways ;-)


Quite right! The cable in question is in a bungalow it runs from
rafter to rafter in the attic and then down behind plaster and tiles to
the fuse box. The cable is clipped to the top surface of each rafter and
has no support until it reaches the next one. Either the cable has been
broken by being stretched between the rafters or there is some fault
behind the fuse box.

I will cut the cable just before it descends and see if I get a neutral.


--
Michael Chare

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

On Sun, 14 Aug 2016 20:00:23 +0100, Michael Chare
wrote:

On 14/08/2016 09:00, Mike Tomlinson wrote:
En el artículo , Michael Chare mUNDERSCOREn
escribió:

This makes me wonder whether I should replace the fuse box with a modern
consumer unit, probably 8 way.

Beware that doing this can show up faults, such as shared neutrals, that
don't affect fused CUs. They can result in an RCD that trips and won't
reset.


The original wiring in this bungalow we recently acquired was done quite
neatly, but unfortunately the property has been modified.

I wanted to remove a 13 amp socket to make it easier to put on wall
paper so I thought I could just pull out the appropriate fuse.

I plugged a lamp into the socket and removed each fuse in turn. The lamp
never went out!

Is your bungalow detached, or could a common owner of your and an
adjacent property have been a little "unconventional".

Personally I would be very concerned if I couldn't identify the source
of my Volts.

Mind You, you could turn off everything in the house and watch the
meter as you plug a heater into the socket, it may help in planning a
heating strategy this winter.

AB


---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

On 14/08/2016 20:00, Michael Chare wrote:
On 14/08/2016 09:00, Mike Tomlinson wrote:
En el artículo , Michael Chare mUNDERSCOREn
escribió:

This makes me wonder whether I should replace the fuse box with a modern
consumer unit, probably 8 way.

Beware that doing this can show up faults, such as shared neutrals, that
don't affect fused CUs. They can result in an RCD that trips and won't
reset.


The original wiring in this bungalow we recently acquired was done quite
neatly, but unfortunately the property has been modified.

I wanted to remove a 13 amp socket to make it easier to put on wall
paper so I thought I could just pull out the appropriate fuse.

I plugged a lamp into the socket and removed each fuse in turn. The lamp
never went out!

Each fuse in turn until you had no fuses at all, or where your replacing
the previous one as you moved to the next?

Its not uncommon to find someone has managed to bridge two circuits
together so that you need to pull two fuses to get the circuit to go dead.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

In article , John Rumm
wrote:
On 14/08/2016 20:00, Michael Chare wrote:
On 14/08/2016 09:00, Mike Tomlinson wrote:
En el artículo , Michael Chare
mUNDERSCOREn escribió:

This makes me wonder whether I should replace the fuse box with a
modern consumer unit, probably 8 way.

Beware that doing this can show up faults, such as shared neutrals,
that don't affect fused CUs. They can result in an RCD that trips and
won't reset.


The original wiring in this bungalow we recently acquired was done
quite neatly, but unfortunately the property has been modified.

I wanted to remove a 13 amp socket to make it easier to put on wall
paper so I thought I could just pull out the appropriate fuse.

I plugged a lamp into the socket and removed each fuse in turn. The
lamp never went out!

Each fuse in turn until you had no fuses at all, or where your replacing
the previous one as you moved to the next?

Its not uncommon to find someone has managed to bridge two circuits
together so that you need to pull two fuses to get the circuit to go dead.

or even a ring with separate fuses at each end.

--
from KT24 in Surrey, England

"charles" wrote in message
...
In article , John Rumm
wrote:
On 14/08/2016 20:00, Michael Chare wrote:
On 14/08/2016 09:00, Mike Tomlinson wrote:
En el artículo , Michael Chare
mUNDERSCOREn escribió:

This makes me wonder whether I should replace the fuse box with a
modern consumer unit, probably 8 way.

Beware that doing this can show up faults, such as shared neutrals,
that don't affect fused CUs. They can result in an RCD that trips and
won't reset.


The original wiring in this bungalow we recently acquired was done
quite neatly, but unfortunately the property has been modified.

I wanted to remove a 13 amp socket to make it easier to put on wall
paper so I thought I could just pull out the appropriate fuse.

I plugged a lamp into the socket and removed each fuse in turn. The
lamp never went out!

Each fuse in turn until you had no fuses at all, or where your replacing
the previous one as you moved to the next?

Its not uncommon to find someone has managed to bridge two circuits
together so that you need to pull two fuses to get the circuit to go
dead.

or even a ring with separate fuses at each end.

Best not mention that this has been done on separate RCDs:-)



--
Adam

On 14/08/2016 12:45, John Rumm wrote:
On 14/08/2016 09:17, Michael Chare wrote:
On 14/08/2016 05:22, John Rumm wrote:

You are likely to find that all 8 way boxes have a very similar layout
and that is likely to be different from your current CU. So arm yourself
with some suitable lengths of wire, and decent quality crimps (+tool) so
that you can extend the ones you need to. (you can also het a bit of
wiggle room by choosing the ordering of the MCBs to suite the wire
lengths you have).

Thanks, I just bought a Screwfix crimp tool to mend my hob!

Would these be suitable crimps:

http://www.ebay.co.uk/itm/100-X-Asso...AOSw3KFWgil T


They look like the right kind, however for this application I would play
safe and order something branded from CPC

Any need for additional insulation such as tape and/or heat shrink?

Not when extending individual wires inside the CU - only if you are
crimping cables outside.

Are RCBOs a good idea?

Yes. All RCBO setups are a top end solution - but it will cost more. It
gives the best levels of RCD discrimination available. (i.e. the effect
of a fault will be limited to the single circuit on which it occurs)

You may find a "high integrity" CU is a good compromise - that's one
where it has at least a couple of banks of MCBs with their own RCD, but
them also a couple of additional non RCD ways that you can fit RCBOs in.
So you can stick circuits with high leakage risk on their own RCBO, but
still lump together low risk circuits on shared RCDs.

Thanks for all your help.

--
Michael Chare

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

En el artículo , Andy Wade spambucke
escribió:

You're supposed to test and assess each circuit before connecting it to
the new CU.

*Supposed*.

This is a group comprised mostly of amateurs with a sprinkling of
professional contributors. I wonder what proportion of us (the group
users) would test each circuit when replacing a CU? Testing would
require the use of equipment that I think most of us wouldn't have,
beyond a multimeter.

I know I didn't test, but connected circuits to the new CU one at a
time, powering on in between.

--
(\_/)
(='.'=) systemd: the Linux version of Windows 10
(")_(")

On 14/08/2016 22:14, John Rumm wrote:

Its not uncommon to find someone has managed to bridge two circuits
together so that you need to pull two fuses to get the circuit to go dead.



Easy to do with a ring where you terminate one end on each fuse, not so
easy with a radial.

On 14/08/2016 22:53, ARW wrote:

or even a ring with separate fuses at each end.

Best not mention that this has been done on separate RCDs:-)




Anyone can make a mistake, its knowing how to find the error that makes
the difference.

On 15/08/2016 08:30, Mike Tomlinson wrote:
En el artículo , Andy Wade spambucke
escribió:

You're supposed to test and assess each circuit before connecting it to
the new CU.

*Supposed*.

This is a group comprised mostly of amateurs with a sprinkling of
professional contributors. I wonder what proportion of us (the group
users) would test each circuit when replacing a CU? Testing would
require the use of equipment that I think most of us wouldn't have,
beyond a multimeter.

I would hope that anyone changing a CU would be able to do at least some
basic tests - even if just with a multimeter. Its going to be the
easiest time to check things like ring continuity, and making sure there
are not obvious earth to neutral shorts since you have access to each
circuits wires in isolation[1].

I know I didn't test, but connected circuits to the new CU one at a
time, powering on in between.

Even that achieved some level of diagnosis - had you connected a circuit
with an earth neutral short or particularly poor insulation resistance,
the RCD trip would have told you which circuit was a likely candidate.
Certainly better then wiring everything up in one hit and then not
knowing what was causing it to trip.

[1] The first time I did a CU swap, I bought the basic test gear s/h
from ebay for £150 (that was for standalone Insulation resistance meter
and low ohms meter, RCD tester, and Earth Loop meter). I knew that I
could always flog it again for much the same money once I was done with
it if I had wanted.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

En el artículo , John
Rumm escribió:

I would hope that anyone changing a CU would be able to do at least some
basic tests - even if just with a multimeter. Its going to be the
easiest time to check things like ring continuity, and making sure there
are not obvious earth to neutral shorts since you have access to each
circuits wires in isolation[1].

Agreed, and yes, I do do that, having changed a few CUs.

Even that achieved some level of diagnosis - had you connected a circuit
with an earth neutral short or particularly poor insulation resistance,
the RCD trip would have told you which circuit was a likely candidate.
Certainly better then wiring everything up in one hit and then not
knowing what was causing it to trip.

Aye.

--
(\_/)
(='.'=) systemd: the Linux version of Windows 10
(")_(")

In article ,
Mike Tomlinson wrote:
This is a group comprised mostly of amateurs with a sprinkling of
professional contributors. I wonder what proportion of us (the group
users) would test each circuit when replacing a CU? Testing would
require the use of equipment that I think most of us wouldn't have,
beyond a multimeter.

I'd certainly test each circuit after installation before connecting to
the CU. Even a simple DVM will show up a major fault like a short. Or open
circuit. And a leaky heater element, etc.

If you have a suspect fault and are installing just a new CU, I'd do the
same. In my experience, the majority of faults will show on an ordinary
DVM if you know how to use it. Although obviously the correct test
equipment is better - but rather too pricey for most DIYers.

--
*Many people quit looking for work when they find a job *

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

John Rumm wrote:

I would hope that anyone changing a CU would be able to do at least some
basic tests - even if just with a multimeter.

I bought an old Robin insulation & continuity tester, an ancient hand
cranked analogue one, years out of calibration even then, but still
works fine ...