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.?

 

[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.