Using generators with class 1 equipment - earth spike?
 

Should an earth spike be used when a generator is used to power class 1
equipment that normally needs an earth? (thinking of safety and ignoring
EMC). I should know the answer to this but can see two sides of the coin
and can't choose between the two.
On one side it would be good to tie the gen and neutral down to Earth,
but on the other side it would seem sensible to let the whole lot float.
... and how would an RCD cope?
The particular case is using a gen to provide power for an outdoor PA
system (and maybe a band).

Dave

"Dave" wrote in message
...
Should an earth spike be used when a generator is used to power class 1
equipment that normally needs an earth? (thinking of safety and ignoring
EMC). I should know the answer to this but can see two sides of the coin
and can't choose between the two.
On one side it would be good to tie the gen and neutral down to Earth,
but on the other side it would seem sensible to let the whole lot float.
.. and how would an RCD cope?
The particular case is using a gen to provide power for an outdoor PA
system (and maybe a band).


Whatever you do, make sure all the mics and guitars have got their own
personal in-line safety isolators.

Too many dead musicians in the past due to poor electrics - of course an
area part pee doesn't cover at all.

"Mike" wrote in message
...

snip[

Too many dead musicians in the past due to poor electrics - of
course an
area part pee doesn't cover at all.


But there was not need for Part P to cover this, other H&S regs cover
it.

Mike wrote:
"Dave" wrote in message
...

Should an earth spike be used when a generator is used to power class 1
equipment that normally needs an earth? (thinking of safety and ignoring
EMC). I should know the answer to this but can see two sides of the coin
and can't choose between the two.
On one side it would be good to tie the gen and neutral down to Earth,
but on the other side it would seem sensible to let the whole lot float.
.. and how would an RCD cope?
The particular case is using a gen to provide power for an outdoor PA
system (and maybe a band).



Whatever you do, make sure all the mics and guitars have got their own
personal in-line safety isolators.

Too many dead musicians in the past due to poor electrics - of course an
area part pee doesn't cover at all.



That's interesting, can you explain a little more. Do you mean isolating
transformers? (or opto-isolators?) I google'd and came up with isolators
to avoid earth loops but nothing about safety.

Dave

"Dave" wrote in message
...
Should an earth spike be used when a generator is used to power class 1
equipment that normally needs an earth? (thinking of safety and ignoring
EMC). I should know the answer to this but can see two sides of the coin
and can't choose between the two.
On one side it would be good to tie the gen and neutral down to Earth,
but on the other side it would seem sensible to let the whole lot float.
.. and how would an RCD cope?
The particular case is using a gen to provide power for an outdoor PA
system (and maybe a band).

Dave


If it is a small 240 volts AC genset, then what do want an earth point on it
for. If you're plugging directly in to the generator, then it already has,
or better have, its own safety devices protecting it and the supply outlets.

A generator doesn't really need an earth point, and some generators don't
really like being pinned to the earth, so you'd need to make sure that the
metal work, if any, around the performance area was insulated from earth,
but not the generator. Blocks of wood under the legs of any metal staging
is usually enough to isolate the stage from earth.

If you're talking industrial generator here, then you'll need to follow the
instructions for the generator you've bought / hired. These sometimes need
to be spiked to earth for their own internal safety features to function
properly. Others need to be bonded to surrounding conductive materials for
the protective devices to work correctly.

It all depends on what and how the generator is going to used.

BigWallop wrote:
"Dave" wrote in message
...

Should an earth spike be used when a generator is used to power class 1
equipment that normally needs an earth? (thinking of safety and ignoring
EMC). I should know the answer to this but can see two sides of the coin
and can't choose between the two.
On one side it would be good to tie the gen and neutral down to Earth,
but on the other side it would seem sensible to let the whole lot float.
.. and how would an RCD cope?
The particular case is using a gen to provide power for an outdoor PA
system (and maybe a band).

Dave



If it is a small 240 volts AC genset, then what do want an earth point on it
for. If you're plugging directly in to the generator, then it already has,
or better have, its own safety devices protecting it and the supply outlets.

A generator doesn't really need an earth point, and some generators don't
really like being pinned to the earth, so you'd need to make sure that the
metal work, if any, around the performance area was insulated from earth,
but not the generator. Blocks of wood under the legs of any metal staging
is usually enough to isolate the stage from earth.

.... snipped

It all depends on what and how the generator is going to used.



It's a small 240 generator, there's an integral overload breaker but not
an RCD. That's spurred a few more questions:
- Why would a generator object to being grounded?
- What is the metalwork on a generator connected to internally?
- If the generator is floating why does any adjacent metalwork need to
be isolated from earth? If it's truly floating there wouldn't be a path
for current to flow.

Dave

"Dave" wrote in message
...
BigWallop wrote:
"Dave" wrote in message
...

snipped

It's a small 240 generator, there's an integral overload breaker but not
an RCD. That's spurred a few more questions:
- Why would a generator object to being grounded?
- What is the metalwork on a generator connected to internally?
- If the generator is floating why does any adjacent metalwork need to
be isolated from earth? If it's truly floating there wouldn't be a path
for current to flow.

Dave


Try a little test for me. With a voltage meter, place one test probe on the
metal casing of the generator. Fix it tightly to the metal. With the other
test probe, touch the Live terminal of the socket outlet. Make a note of
the voltage reading it shows. Now touch the Neutral terminal and make a
note of the voltage it has.

Now do a little bit of maths, simple addition, and add both the reading
together. What do you get?

A generator doesn't have to have an earth point to ground, and some
generators are more dangerous if they are fixed electrically to earth
ground. It does depend on the generator though, and the in-built safety
features it already has.

Dave wrote:

That's interesting, can you explain a little more. Do you mean isolating
transformers? (or opto-isolators?) I google'd and came up with isolators
to avoid earth loops but nothing about safety.

I think he means RCDs.....

Usual practice for small gigs is a 30mA rcd either at the generator (which
gives no discrimination), or several at thee distribution board.
I often add a 10mA unit just for the backline because backline tends to be
the root of all evil in this matter.

Do earth the generator frame with a spike, and DO bond the stage metalwork
to generator earth (it probably will be via some path anyway and you would
rather this didn't involve the screen of the audio snake....).

The spike is to protect you the generator operator in the event of an
internal fault imposing voltage between the generator frame and the earth
connection on the socket which is probably earthed elsewhere (like say the
stage).

The RCD(s) protect the musicians from faults in the distro and their guitar
amps (what never!).

Bonding the stage metalwork reduces possible earth loop impedance issues and
encourages faster disconnect times.

Really once you get past the genny it is all fairly standard event power
engineering.

HTH.

Regards, Dan.

On Fri, 13 May 2005 18:12:20 +0000 (UTC), Dave wrote:

Should an earth spike be used when a generator is used to power
class 1 equipment that normally needs an earth?

Yes, and bond the generator chassis to that spike and to which ever
phase from the alternator you decide to call "neutral". ie replicate
the sort of supply that the equipment is designed to be plugged into.
A protective earth wire connected to real ground via a spike, neutral
bonded to that earth at the supply source (generator).

On one side it would be good to tie the gen and neutral down to
Earth, but on the other side it would seem sensible to let the whole
lot float.

Letting the neutral float is not good. One fault and that phase
becomes as near as damn it earth potential but the other is now 240v
away from earth. If that fault is in the live side the neutral is now
sitting at 240v WRT earth. Single pole switches and/or single pole
fuses, some thing looks off but is still very much live.

... and how would an RCD cope?

An RCD doesn't care about earths or lack of. All it cares about is
that the same amount of current going to the load comes back (within a
few tens of mA). If there is a current inbalance the difference must
be going somewhere else which is probably A Bad Thing.

So put in a spike at the generator bond that to the generator chassis,
bond a phase from the alternator to the chassis and earth spike and
use an RCD.

--
Cheers
Dave. pam is missing e-mail

You need to read the relevant section of BS7671 which I don't
have to hand, and I don't remember that section off the top of
my head, but I've guessed some answers below.

"Dave" wrote in message
...
Should an earth spike be used when a generator is used to power class 1
equipment that normally needs an earth? (thinking of safety and ignoring

Yes.

EMC). I should know the answer to this but can see two sides of the coin
and can't choose between the two.
On one side it would be good to tie the gen and neutral down to Earth,
but on the other side it would seem sensible to let the whole lot float.
.. and how would an RCD cope?
The particular case is using a gen to provide power for an outdoor PA
system (and maybe a band).

If the generator was supplying only one appliance, you could regard
it as an isolated floating supply or an IT earthing system. However,
as soon as you are driving multiple appliances (particularly something
like an outdoor PA/band), it's not isolated anymore, and you probably
need to make it a TT earthing system. In either case, the wiring regs
still apply to the whole installation.

--
Andrew Gabriel

BigWallop wrote:

A generator doesn't have to have an earth point to ground, and some
generators are more dangerous if they are fixed electrically to earth
ground. It does depend on the generator though, and the in-built safety
features it already has.

Cite please?

I don't think I have EVER seen a general purpose generator which did NOT
have either the star point OR the neutral end of the winding (if single
phase) tied to both the ground terminal and the case!

Sure you can argue that an IT system is safer (but only if it has a earth
fault detector) then a conventionally earthed system, but I don't think I
have ever seen it done on an event site.

For any normal event power generator, drive a local earth stake and bond all
the exposed metalwork to it (including the stage structure if appropriate)
and make sure you use RCDs in the distro.

Regards, Dan.

"Dave" wrote in message
...



Whatever you do, make sure all the mics and guitars have got their own
personal in-line safety isolators.

Too many dead musicians in the past due to poor electrics - of course an
area part pee doesn't cover at all.


That's interesting, can you explain a little more. Do you mean isolating
transformers? (or opto-isolators?) I google'd and came up with isolators
to avoid earth loops but nothing about safety.

Most guitarists will have one of these or similar already. Get something
similar for any non radio handheld mics you provide.

http://www.bss.co.uk/includes/produc...#attachmen ts

But of course you should also have RCDs in the supplies as other have
mentioned.

BigWallop wrote:

If it is a small 240 volts AC genset, then what do want an earth
point on it
for. If you're plugging directly in to the generator, then it already
has,
or better have, its own safety devices protecting it and the supply
outlets.

A generator doesn't really need an earth point, and some generators
don't
really like being pinned to the earth, so you'd need to make sure
that the
metal work, if any, around the performance area was insulated from
earth,
but not the generator. Blocks of wood under the legs of any metal
staging
is usually enough to isolate the stage from earth.

truly, no, this is not a Good Idea (tm).

NT

In article ,
Mike wrote:
Whatever you do, make sure all the mics and guitars have got their own
personal in-line safety isolators.

Too many dead musicians in the past due to poor electrics - of course an
area part pee doesn't cover at all.

Often down to faulty instruments or PA systems. The common way these days
is to PAT them all before use. Older method was to use a mains isolation
transformer on each and every instrument. But this was in the days of
valve amps where some didn't include their own internal isolating
transformers. Most solid state gear will, as it runs off a lower voltage
'HT' rail.

We often have a 100 KVA genny out for filming where mains isn't
available. And I don't *think* they sink an earth spike. They run a 45 amp
(or two) circuit to a sort of rugged CU, and 15 amp circuits from that.
I'm not actually sure what sort of breakers are in that CU, though.
I'll ask on Monday.

--
*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 om,
Dave Liquorice wrote:
Should an earth spike be used when a generator is used to power
class 1 equipment that normally needs an earth?

Yes, and bond the generator chassis to that spike and to which ever
phase from the alternator you decide to call "neutral". ie replicate
the sort of supply that the equipment is designed to be plugged into.
A protective earth wire connected to real ground via a spike, neutral
bonded to that earth at the supply source (generator).

Is this the practice when you have a genny on location, Dave?

I'm pretty certain Lee Electrics don't do this with us, but not absolutely
certain. But we have a genny out on Monday so I'll try and get chapter and
verse from the operator.

--
*Of course I'm against sin; I'm against anything that I'm too old to enjoy.

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

In article ,
Mike wrote:
That's interesting, can you explain a little more. Do you mean
isolating transformers? (or opto-isolators?) I google'd and came up
with isolators to avoid earth loops but nothing about safety.

Most guitarists will have one of these or similar already. Get
something similar for any non radio handheld mics you provide.

You're joking? Never ever seen this done. For a start, most decent mics
are phantom powered, so need a DC path on screen and both signal lines.

Of course vocal mics are often non powered types, but I'd not be keen on
introducing an extra transformer there. I'd say all mixers if CE approved
etc will be perfectly safe if fed from a safe power supply, so I'd make
that the route to follow.

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

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

Dave Plowman (News) wrote:
In article ,
Mike wrote:
Whatever you do, make sure all the mics and guitars have got their
own
personal in-line safety isolators.

Too many dead musicians in the past due to poor electrics - of
course an
area part pee doesn't cover at all.

Often down to faulty instruments or PA systems. The common way these
days
is to PAT them all before use. Older method was to use a mains
isolation
transformer on each and every instrument. But this was in the days of
valve amps where some didn't include their own internal isolating
transformers. Most solid state gear will, as it runs off a lower
voltage
'HT' rail.

We often have a 100 KVA genny out for filming where mains isn't
available. And I don't *think* they sink an earth spike. They run a
45 amp
(or two) circuit to a sort of rugged CU, and 15 amp circuits from
that.
I'm not actually sure what sort of breakers are in that CU, though.
I'll ask on Monday.

I'm guessing that the metal frame of a 100kVA gen would make good
connection with earth without any spike.

NT

In article .com,
wrote:
We often have a 100 KVA genny out for filming where mains isn't
available. And I don't *think* they sink an earth spike. They run a 45
amp (or two) circuit to a sort of rugged CU, and 15 amp circuits from
that. I'm not actually sure what sort of breakers are in that CU,
though. I'll ask on Monday.

I'm guessing that the metal frame of a 100kVA gen would make good
connection with earth without any spike.

Years ago when I worked on large OBs with gennys large enough to run
several scanners with air-con, they *did* sink an earth rod. But export
mains to remotes perhaps a mile away using a multicores - and joints -
which had mains and several video and audio circuits all in one. Makes I
laugh at the how do I get power to my shed type questions. ;-)

--
*Change is inevitable, except from a vending machine.

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

On Sat, 14 May 2005 11:37:54 +0100, Dave Plowman (News) wrote:

Yes, and bond the generator chassis to that spike and to which ever
phase from the alternator you decide to call "neutral". ie
replicate the sort of supply that the equipment is designed to be
plugged into. A protective earth wire connected to real ground via
a spike, neutral bonded to that earth at the supply source
(generator).

Is this the practice when you have a genny on location, Dave?

Firstly this is for a single phase supply from a alternator with a
single winding. Don't know about 3 phase, with star connected the
central point is "neutral" and I think would be earth bonded at the
source. Delta connected, I think there is still a "neutral" wire so
like wise.

On a single winding alternator (ie two phases 180 deg apart) I'm
99.99% sure. Though the "earth spike" may just be laid on the tarmac
and one of the wheels driven onto it... If there is a handy bit of
open ground I have seen them hammered in but more often than not it's
simply parked on.

I'm pretty certain Lee Electrics don't do this with us, but not
absolutely certain. But we have a genny out on Monday so I'll try
and get chapter and verse from the operator.

Be interesting to know, I really don't like the idea of a floating
neutral for the reasons I stated earlier. Ordinary equipment is not
designed to be "safe" with the neutral floating, single pole switches
and fuses in the live only etc.

I expect we'll be off a generator at St James's Park tommorow. If I
can track down the operator I'll ask as well.

--
Cheers
Dave. pam is missing e-mail

On Sat, 14 May 2005 14:51:00 +0100, Dave Plowman (News) wrote:

I'm guessing that the metal frame of a 100kVA gen would make good
connection with earth without any spike.

Not when the genny is built into the sound proof back of a truck with
nice big rubber tyres between the chassis and the ground...

Years ago when I worked on large OBs with gennys large enough to run
several scanners with air-con, they *did* sink an earth rod.

Conversely I have never seen a generator in use without an earth spike
out at the generator, it might just be parked on but it's always
there.

But export mains to remotes perhaps a mile away using a multicores -
and joints - which had mains and several video and audio circuits
all in one. Makes I laugh at the how do I get power to my shed type
questions. ;-)

All those exported feeds are RCD protected and I think in the case of
MkVII interlocked, no mains on the cable unless there is a box on the
end.

--
Cheers
Dave. pam is missing e-mail

wrote in message ...
On 13 May,

SNIP


We hired a generator from a reputable firm to plug into a fixed socket to
supply fixed equipment via a changeover switch during a mains outage. The
generator was 230 volts and had it's centre tap earthed, giving 115-0-115
output relative to earth. On the fixed wiring was a fault, not showing
normally of an earthed neutral. This resulted in a lot of fried wiring.
Without the earth spike/bonding it could have been fried operator. It is
essential that for a temporary arrangement all safety checks are carried
out
*and* earthing arrangements verified.


The fact that the portable geny had an earthed centre tap would make it
extremely UNsuitable for use with an external earthed output leg. As you say
it is essential that whoever installs the system fully verifies it.
You could of course argue that having a maximum of 115 volts to earth shock
potential from the source would make it safer to use and a double pole 30mA
RCD on the geny output should detect (and isolate) any imbalance or leakage
to earth current.

In message .com,
writes
I'm guessing that the metal frame of a 100kVA gen would make good
connection with earth without any spike.

Not when it is part of a truck.


NT


--
Bill

In message , "Dave Plowman (News)"
writes

I'm pretty certain Lee Electrics don't do this with us, but not absolutely
certain. But we have a genny out on Monday so I'll try and get chapter and
verse from the operator.
Did you know Joe from Lee? He did a lot of the Beeb golf OB's an
interesting character!!!!!!!!!!!


--
Bill

In article ,
Bill wrote:
I'm pretty certain Lee Electrics don't do this with us, but not
absolutely certain. But we have a genny out on Monday so I'll try and
get chapter and verse from the operator.

Did you know Joe from Lee? He did a lot of the Beeb golf OB's an
interesting character!!!!!!!!!!!

Not offhand, but I'd guess they employ hundreds. And we don't normally use
the large gennys you'd get on golf, etc.

And most sparks are characters. ;-)

--
*Do infants enjoy infancy as much as adults enjoy adultery?

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

On Fri, 13 May 2005 22:55:03 +0100, Dan Mills
wrote:


I don't think I have EVER seen a general purpose generator which did NOT
have either the star point OR the neutral end of the winding (if single
phase) tied to both the ground terminal and the case!

I have two single phase general purpose generators both of which
earth at the midpoint between neutral and line - 110v.

--
Peter Parry.
http://www.wpp.ltd.uk/

Peter Parry wrote:

On Fri, 13 May 2005 22:55:03 +0100, Dan Mills
wrote:


I don't think I have EVER seen a general purpose generator which did NOT
have either the star point OR the neutral end of the winding (if single
phase) tied to both the ground terminal and the case!

I have two single phase general purpose generators both of which
earth at the midpoint between neutral and line - 110v.

Ahh, sorry I should have added 240V as a rider on that, given we were
talking event power it seemed reasonable to assume....

55-0-55 is of course standard for building site power tools.

Regards, Dan.

On Mon, 16 May 2005 19:14:55 +0100, Dan Mills
wrote:

Peter Parry wrote:

Ahh, sorry I should have added 240V as a rider on that, given we were
talking event power it seemed reasonable to assume....

55-0-55 is of course standard for building site power tools.

My apologies, I meant 240VAC with the earth at 110V so 110-0-110.

--
Peter Parry.
http://www.wpp.ltd.uk/

Dan Mills wrote:
Dave wrote:


That's interesting, can you explain a little more. Do you mean isolating
transformers? (or opto-isolators?) I google'd and came up with isolators
to avoid earth loops but nothing about safety.


I think he means RCDs.....

Usual practice for small gigs is a 30mA rcd either at the generator (which
gives no discrimination), or several at thee distribution board.
I often add a 10mA unit just for the backline because backline tends to be
the root of all evil in this matter.

Do earth the generator frame with a spike, and DO bond the stage metalwork
to generator earth (it probably will be via some path anyway and you would
rather this didn't involve the screen of the audio snake....).

The spike is to protect you the generator operator in the event of an
internal fault imposing voltage between the generator frame and the earth
connection on the socket which is probably earthed elsewhere (like say the
stage).

The RCD(s) protect the musicians from faults in the distro and their guitar
amps (what never!).

Bonding the stage metalwork reduces possible earth loop impedance issues and
encourages faster disconnect times.

Really once you get past the genny it is all fairly standard event power
engineering.

HTH.

Regards, Dan.

Thanks Dan, very useful. The gig went ahead successfully, the only
problem was that we couldn't get the earth spike out so had to hammer it
further into the ground.

Dave

Dave Plowman (News) wrote:
.... snipped
We often have a 100 KVA genny out for filming where mains isn't
available. And I don't *think* they sink an earth spike. They run a 45 amp
(or two) circuit to a sort of rugged CU, and 15 amp circuits from that.
I'm not actually sure what sort of breakers are in that CU, though.
I'll ask on Monday.


Did you ask?

Dave

Peter Parry wrote:

On Mon, 16 May 2005 19:14:55 +0100, Dan Mills
wrote:

Peter Parry wrote:

Ahh, sorry I should have added 240V as a rider on that, given we were
talking event power it seemed reasonable to assume....

55-0-55 is of course standard for building site power tools.

My apologies, I meant 240VAC with the earth at 110V so 110-0-110.


OUCH!
Given that UK practice only fuses (and switches) one leg (and in fact that I
have seen RCDs that only switch one leg), how could this ever be viewed as
safe in the UK?

It is standard in America where most domestic power is done this way, but I
cannot see such a thing as being safe in the UK.

Regards, Dan (Very surprised to hear about this).

In article ,
Dave wrote:
We often have a 100 KVA genny out for filming where mains isn't
available. And I don't *think* they sink an earth spike. They run a 45
amp (or two) circuit to a sort of rugged CU, and 15 amp circuits from
that. I'm not actually sure what sort of breakers are in that CU,
though. I'll ask on Monday.


Did you ask?

Fooking ran on batteries all day because of no genny. So no heating in the
van - and there was a cold wind. Tomorrow, definitely a genny. A wasteland
in Greenwich. ;-)

And and 0.700 start so I'm off to bed...

--
*You're just jealous because the voices only talk to me *

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

On Tue, 17 May 2005 22:42:56 +0100, Dave Plowman (News) wrote:

Fooking ran on batteries all day because of no genny. So no heating
in the van - and there was a cold wind.

A van? A VAN! Get out there man with yer trolly and brolly. Namby
pamby sutherners. B-)

I forgot to ask at St James's Park. One of the nice twin sets as well
rather than a single.

--
Cheers
Dave. pam is missing e-mail

In article om,
Dave Liquorice wrote:
Fooking ran on batteries all day because of no genny. So no heating
in the van - and there was a cold wind.

A van? A VAN! Get out there man with yer trolly and brolly. Namby
pamby sutherners. B-)

But we don't grade the pictures afterwards. So the LD needs a controlled
lighting environment to adjust the camera correctly. Ie a blacked out rear
crew area of a van. And I like my own space too. ;-) Easier to concentrate
- and I can use a speaker for rehearsals.

Ok. Soft southerners. ;-)


I forgot to ask at St James's Park. One of the nice twin sets as well
rather than a single.

The 100KVA genny simply parked on concrete with its earth rod under one
front wheel. Each 'CU' has a main RCD, and RCDs feeding each circuit from
it. Neutral not tied to earth - although I'm told some do. Warning lights
on the 'CU' for polarity reversal. We were running single phase.

--
*Toilet stolen from police station. Cops have nothing to go on.

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

"Dave Plowman (News)" wrote in message
...
snip

--
*Toilet stolen from police station. Cops have nothing to go on.


Been peaking at the next script Dave ?!.... :~)

In article ws.net,
:::Jerry:::: wrote:
*Toilet stolen from police station. Cops have nothing to go on.

Been peaking at the next script Dave ?!.... :~)

No. That would be that after an alien attack from the planet Zog the same
sex uniforms rape one another in the writing room. It's part of the set
that needs using. Then, after their families get wiped out by a massive
sunspot, they convert to Buddhism. Absolutely PC. And Terry and Rimini
have a whispered conversation that only they can hear - almost. Below the
noise of the genny which can't be situated where I wanted it because they
haven't got long enough cables. Oh yes.
Tomorrow, under the arches a few metres from Clapham Junction. Trains
every 30 seconds. Which at least will drown out the helicopters. But I
don't care. I'll start writing crappy poetry.

--
*A bicycle can't stand alone because it's two tyred.*

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

On Wed, 18 May 2005 19:12:13 +0100, Dave Plowman (News) wrote:

The 100KVA genny simply parked on concrete with its earth rod under
one front wheel.

That is "normal".

Each 'CU' has a main RCD, and RCDs feeding each circuit from it.
Neutral not tied to earth - although I'm told some do.

With *everything* through RCDs the N - E bond is not quite so
important. A L - E fault will probably cause a big enough inbalance to
trip one of the RCDs. Even if it doesn't anyone coming into contact
the now "live" E will trip the RCD.

--
Cheers
Dave. pam is missing e-mail

Dave Plowman (News) wrote:
*Toilet stolen from police station. Cops have nothing to go on.
Been peaking at the next script Dave ?!.... :~)
No. That would be that after an alien attack from the planet Zog the same
sex uniforms rape one another in the writing room.

Oh no, not *another* Gay Sex That Shocks The Tabloid Headline Writers
episode. I can't imagine anything more frightening than Gina Gold and
June Ackland in Hot Lesbian Truncheon Action :-)

Owain