I have bought a Grant external boiler for the renovation.

I have a couple of questions re the electrical connection.

As regards supplementary bonding to the oil feed pipe, is this required
if the boiler is outside? The internal plumbing will be all plastic
after the first metre.

The manual states that "The electrical supply to the boiler and control
system should be fed from a single separate 5 Amp circuit breaker with
earth leakage protection providing complete electrical isolation". Also
a fused double pole switch should be used. I was planning to just use a
FCU on the downstairs ring to provide power. Is the separate circuit
breaker (MCB?) really necessary?

Cheers

Martin

--
Martin Carroll

Martin Carroll wrote:

I have bought a Grant external boiler for the renovation.

I have a couple of questions re the electrical connection.

As regards supplementary bonding to the oil feed pipe, is this required
if the boiler is outside? The internal plumbing will be all plastic
after the first metre.

If its all plastic in the house, then I can't see the need.

The manual states that "The electrical supply to the boiler and control
system should be fed from a single separate 5 Amp circuit breaker with
earth leakage protection providing complete electrical isolation". Also
a fused double pole switch should be used. I was planning to just use a
FCU on the downstairs ring to provide power. Is the separate circuit
breaker (MCB?) really necessary?

Not required, but perhaps desirable. Boilers and appliances outside are
good candidates for nuisance trip problems, so not sharing a RCD with
your socket circuit could have advantages.

--
Cheers,

John.

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

On 31 Jan, 15:34, John Rumm wrote:
Martin Carroll wrote:
I have bought a Grant external boiler for the renovation.

I have a couple of questions re the electrical connection.

As regards supplementary bonding to the oil feed pipe, is this required
if the boiler is outside? *The internal plumbing will be all plastic
after the first metre.

If its all plastic in the house, then I can't see the need.

The manual states that "The electrical supply to the boiler and control
system should be fed from a single separate 5 Amp circuit breaker with
earth leakage protection providing complete electrical isolation". Also
a fused double pole switch should be used. *I was planning to just use a
FCU on the downstairs ring to provide power. *Is the separate circuit
breaker (MCB?) really necessary?

Not required, but perhaps desirable. Boilers and appliances outside are
good candidates for nuisance trip problems, so not sharing a RCD with
your socket circuit could have advantages.

--
Cheers,

John.

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

"good candidates for nuisance trip" Hmm - interesting. I've three
external circuits - outside boiler, outside workshop and outside
garage/greenhouse/storage shed and in 25 years I've never had a
problem. Perhaps as an amateur I do a good job of wiring !!!

Of course having just said that, they will now all give me hell!

Rob

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember Martin Carroll
saying something like:

The manual states that "The electrical supply to the boiler and control
system should be fed from a single separate 5 Amp circuit breaker with
earth leakage protection providing complete electrical isolation". Also
a fused double pole switch should be used. I was planning to just use a
FCU on the downstairs ring to provide power. Is the separate circuit
breaker (MCB?) really necessary?

Do like 99% of installers do and take a spur from the protected ring to
a switched double socket at the boiler with the boiler and pump plugged
in with 5A fuses in the plugs. Does all you need and safely, too, for
servicing.

robgraham wrote:

"good candidates for nuisance trip" Hmm - interesting. I've three
external circuits - outside boiler, outside workshop and outside
garage/greenhouse/storage shed and in 25 years I've never had a
problem. Perhaps as an amateur I do a good job of wiring !!!

Of course having just said that, they will now all give me hell!

As with all these things, you can only go with probabilities. There is
no guarantee that any setup will cause a problem and none that it won't.
So its just a case of working out what is possible or likely, and
deciding on how important the implications of it are. Circuits that
potentially involve dampness, water, high humidity etc are more likely
to cause problems (as are ones with copious mains IF filters or mineral
insulated heating elements). Then again in reality they may work
faultlessly.

--
Cheers,

John.

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

"robgraham" wrote in message
...
On 31 Jan, 15:34, John Rumm wrote:
Martin Carroll wrote:
I have bought a Grant external boiler for the renovation.

I have a couple of questions re the electrical connection.

As regards supplementary bonding to the oil feed pipe, is this required
if the boiler is outside? The internal plumbing will be all plastic
after the first metre.

If its all plastic in the house, then I can't see the need.

The manual states that "The electrical supply to the boiler and control
system should be fed from a single separate 5 Amp circuit breaker with
earth leakage protection providing complete electrical isolation". Also
a fused double pole switch should be used. I was planning to just use a
FCU on the downstairs ring to provide power. Is the separate circuit
breaker (MCB?) really necessary?

Not required, but perhaps desirable. Boilers and appliances outside are
good candidates for nuisance trip problems, so not sharing a RCD with
your socket circuit could have advantages.

--
Cheers,

John.

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

"good candidates for nuisance trip" Hmm - interesting. I've three
external circuits - outside boiler, outside workshop and outside
garage/greenhouse/storage shed and in 25 years I've never had a
problem. Perhaps as an amateur I do a good job of wiring !!!

Of course having just said that, they will now all give me hell!

Rob


This is not a comment on any of your work Rob but a serious question, but
have you tested the RCD in the last 25 years?

I have come across several RCDs that will not trip when they are supposed
to.

Adam

On Sat, 31 Jan 2009 15:08:56 +0000 someone who may be Martin Carroll
wrote this:-

The manual states that "The electrical supply to the boiler and control
system should be fed from a single separate 5 Amp circuit breaker with
earth leakage protection providing complete electrical isolation".

They appear to be confused, or need to introduce some commas. Earth
leakage protection is not designed to provide complete electrical
isolation, although a suitable double-pole RCD will do so.

There is something to be said for a dedicated radial circuit to a
boiler, with a fuse or MCB in the consumer unit. What else is
desirable or necessary depends on where the boiler is located. An
outbuilding, a separate boiler house, a separate building, outdoors
(unlikely, but possible) and so on. Then there is a similar question
with regard to the oil tank. The answers to the questions will help
with answers to questions on things like bonding.



--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

In article , David Hansen
writes
There is something to be said for a dedicated radial circuit to a
boiler, with a fuse or MCB in the consumer unit. What else is
desirable or necessary depends on where the boiler is located. An
outbuilding, a separate boiler house, a separate building, outdoors
(unlikely, but possible) and so on.

The boiler is indeed an outdoor model, http://www.grantuk.com/product/29

Cheers

Martin

--
Martin Carroll