Isolation switch for boiler supply?

[cadspark]

Been asked to look at a house on a small development completed about 5 years ago. Really messy situation involving builders and houses having no completion certificates or even planning permission in one case. Gas central heating is installed but the boiler is wired up straight to a 6 amp circuit breaker with no means of isolating seperately. As the boiler and cu are both in the kitchen would you deem the circuit breaker as adequate as a means of isolation if not ideal as installing a switch would involve messy chasing and retiling work.?

 

[Moses]

Ideally a DP isolator must be fitted when doing an install.

However, if its already installed, then the Isolator in the CU should be sufficient.

 

[LineProducts]

The mcb won't give you the dp disconnect. 554.3.3

Is there any space behind the boiler cover or just under for a surface mount breaker?

 

[Geordie Spark]

Ideally a DP isolator must be fitted when doing an install.

However, if its already installed, then the Isolator in the CU should be sufficient.

If my memory serves me correctly, isolation needs to be provided near to the boiler & this bust be by either a double pole switch or a plug top plugged into a socket. Either way, a 3 amp fuse should be fitted.

 

[sedgy34]

fit a sw/spur under boiler 3amp fuse

 

[rich.250]

^^agree^^
Local isolation required.

 

[D Skelton]

Ideally a DP isolator m̶u̶s̶t̶ should be fitted when doing an install.

However, if its already installed, then the Isolator in the CU should be sufficient.

The mcb won't give you the dp disconnect. 554.3.3

No, but the DP main switch will.

If my memory serves me correctly, isolation needs to be provided near to the boiler & this bust be by either a double pole switch or a plug top plugged into a socket. Either way, a 3 amp fuse should be fitted.

^^agree^^
Local isolation required.

The use of an MCB and/or main switch and/or RCD is a perfectly acceptable means of switching off an appliance for mechanical maintainence. Nowhere does it state in BS 7671 that switching off/isolation for mechanical maintainence must be provided locally. As stated above, isolation can be achieved via the DP main switch.


In response to the OP, if the CU is readily accessible then the install complies with Reg 132.15.2 so no need to fit any other switches.

 

[rich.250]

I dont think isolating the whole installation is adequate for routine maintenance on the boiler....

 

[D Skelton]

Of course it's adequate! But there's no need as it has its own MCB

 

[rich.250]

- a device for switching off for mechanical maintenance shall be so placed and durably marked so as to be readily identifiable and convenient for intended use.

So a cb would be ok, but would need to be identified at the boiler.

 

[D Skelton]

You are correct, hence why I said that if the CU was readily accessible, then no other switch needed. But you're right in the sense that it is common practice (often a must) to provide a local means of switching off, just not on this occasion.

 

[rich.250]

Yes. I have now read that part of your post. Lol.
My mistake.

Although, I do have my doubts a boiler engineer will be able to find the boiler circuit LOL

 

[D Skelton]

Haha! agreed!

 

[oba]

If the dist board is local to boiler can you not fit a surface fcu labeled up, at the dist board - dp local isolation minimal disruption in the event of needing to isolate the boiler and no chasing

 

[D Skelton]

If the dist board is local to boiler can you not fit a surface fcu labeled up, at the dist board - dp local isolation minimal disruption in the event of needing to isolate the boiler and no chasing

What would be the point of that when the boiler is on an MCB anyway?

dp local isolation

And what is it with this phrase?! It's so commonly used and yet nowhere in the BGB does this phrase appear!

 

[oba]

And the British gas bloke is going to find the mcb before he isolates the down ring/kitchen ring/intruder alarm I guess?
Isolates ALL live conductors
faulty boiler n-e problems can be isolated minimising disruption in the event of a fault
complies with manufactures instructions
3A fuse
................:clap:

 

[PC Electrics]

Been asked to look at a house on a small development completed about 5 years ago. Really messy situation involving builders and houses having no completion certificates or even planning permission in one case. Gas central heating is installed but the boiler is wired up straight to a 6 amp circuit breaker with no means of isolating seperately. As the boiler and cu are both in the kitchen would you deem the circuit breaker as adequate as a means of isolation if not ideal as installing a switch would involve messy chasing and retiling work.?

Gas regulations require that gas boilers must be protected by a 3A fuse.

From a purely electrical / 7671 pov you could use the MCB as an isolator, but you would still have to fit an unswFCU with a 3A fuse. So you might as well fit a swFCU, preferably a DP one.

 

[PC Electrics]

What would be the point of that when the boiler is on an MCB anyway?

See post #17 above.

This is one of those cases where an electrician must be aware of regulations other than just BS7671 when completing work.

 

[D Skelton]

Gas regulations require that gas boilers must be protected by a 3A fuse.

What about boilers that use more than three amps?

Be a stonkingly massive boiler! But a boiler none the less

 

[oba]

That would be an immersion heater

 

[kingeri]

This does highlight the need to be up on building regs, gas regs etc. 7671 isn't the be all and end all of what we do as sparks.

 

[rich.250]

Very true!

 

[Moses]

You are correct, hence why I said that if the CU was readily accessible, then no other switch needed. But you're right in the sense that it is common practice (often a must) to provide a local means of switching off, just not on this occasion.

In Most properties the CU is hidden away in a corner cupboard with massive furniture in front, or a big TV trolly with a big 60" TV on it. You move it at your own risk. That's why a boiler/washing machine/ dish washer DP spur is a must at the time of new install and is best practice.

 

[cadspark]

Well that what was quite a healthy debate and leaves me with quite a bit to think about. Thanks as ever to all respondents for your replies. This whole development is turning into a can of worms with other issues such as lack of bonding. I'm booked to do two EICR's for householders and i'm not sure what may come as as a result!

 

[Rockingit]

You could always swap the MCB for a 3A RCBO (if you can get one!), put a notice on the boiler for where to isolate it and that would keep everyone happy!

 

[Geordie Spark]

No, but the DP main switch will.




The use of an MCB and/or main switch and/or RCD is a perfectly acceptable means of switching off an appliance for mechanical maintainence. Nowhere does it state in BS 7671 that switching off/isolation for mechanical maintainence must be provided locally. As stated above, isolation can be achieved via the DP main switch.


In response to the OP, if the CU is readily accessible then the install complies with Reg 132.15.2 so no need to fit any other switches.

Maybe not, but every copy of the boiler manufacturers instructions that I've ever seen clearly states that either a switched fused spur or a plug top & socket fitted with a 3 amp fuse shall be used.

I was always under the impression that the manufacturers instructions were to be followed over & above anything else.

 

[Geordie Spark]

You could always swap the MCB for a 3A RCBO (if you can get one!), put a notice on the boiler for where to isolate it and that would keep everyone happy!

Yes, but it would need to be a Double Pole 3A RCBO ............ if you can get one

 

[ontimeelectics]

I am a gas safe engineer. Manufacturers request a means of isolation near boiler - can be socket provided socket is UNSWITCHED.

 

[Silly Sausage]

Would a double pole switched socket be acceptable?

 

[ontimeelectics]

The basis is that customer can only disconnect by removing plug - switched would let them just switch off for isolation. DP isolation is required.

 

[telectrix]

the reson we don't fit switched sockets is so that numpty customer can't inadvertently switch it off and then get a £120 bill from BG to switch it back on. why then is a switched FCU acceptale ?

 

[DPG]

No, but the DP main switch will.




The use of an MCB and/or main switch and/or RCD is a perfectly acceptable means of switching off an appliance for mechanical maintainence. Nowhere does it state in BS 7671 that switching off/isolation for mechanical maintainence must be provided locally. As stated above, isolation can be achieved via the DP main switch.


In response to the OP, if the CU is readily accessible then the install complies with Reg 132.15.2 so no need to fit any other switches.

Surely going by this, fan isolators aren't necessary then? Daz

 

[Silly Sausage]

the reson we don't fit switched sockets is so that numpty customer can't inadvertently switch it off and then get a £120 bill from BG to switch it back on. why then is a switched FCU acceptale ?

Did the world go mad when I was in a drunken stupor!
Hahahaha! Love it!



Only 62 to go...I'll see you there GS

 

[telectrix]

61....

 

[Geordie Spark]

Did the world go mad when I was in a drunken stupor!
Hahahaha! Love it!



Only 62 to go...I'll see you there GS

Champion bonny lad!!

It's bloody lonely - and cold - in there this time of year. Maybe we can have a game of Tumbleweed Football to keep ourselves warm?

 

[Silly Sausage]

Champion bonny lad!!

It's bloody lonely - and cold - in there this time of year. Maybe we can have a game of Tumbleweed Football to keep ourselves warm?

I'm all toasty and warm sat next to my recently installed multi fuel burner stove thingy, fitted by myself complete with totally dodgy flue work! Probably contravened Part Fknowswhat and unnotified. Let me burn in Hell!

 

[ayjay]

just move the cu nearer the boiler?


i,ll get my coat--------

 

[JulianC]

Surely going by this, fan isolators aren't necessary then? Daz

They aren't. Unless your khazi has no windows and the fan runs off the lighting circuit, in which case the Electrician's Guide to the Building Regs. suggests the fan should have it's own means of isolation so you don't carry out maintenance in the dark. Alternatively, wear a headtorch.

 

[Geordie Spark]

I'm all toasty and warm sat next to my recently installed multi fuel burner stove thingy, fitted by myself complete with totally dodgy flue work! Probably contravened Part Fknowswhat and unnotified. Let me burn in Hell!

You got a piccie of it???

 

[decolad69]

How about an engraved label on the front of the boiler identifying the circuit at the consumer unit and if required a FCU next too the consumer unit marked 'boiler'

 

[sedgy34]

I'm all toasty and warm sat next to my recently installed multi fuel burner stove thingy, fitted by myself complete with totally dodgy flue work! Probably contravened Part Fknowswhat and unnotified. Let me burn in Hell!

Burn? More like poisoning yourself

 

[D Skelton]

Surely going by this, fan isolators aren't necessary then? Daz

You're right, they're not.

 

[Octopus]

You're right, they're not.

They aren't necessary but good practice.

I'll put my wooden spoon away now

PLUS the last two calls I've been to with nuisance tripping were both caused by boilers. Luckily both had DP switches!

 

[D Skelton]

They aren't necessary but good practice.

Of course, I'll never dispute that.

 

[kingeri]

The world seems to have gone isolator mad these days!

 

[Octopus]

The world seems to have gone isolator mad these days!

I'd say the world has gone RCD mad and thus isolators are more important than ever!