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!