BS7671 524.1, C2 or C3

[Tunni]

Hi folks, doing an EICR yesterday and I came across a domestic boiler, installed in Feb this year, it has been wired to the FCU in 0.75mm CSA flex. The FCU has a 3A fuse. Obviously this is bull and the plumber/installer needs to come back and use the right darn cable. Meantime I am about to type up the EICR. Code 2 or Code 3. Baring in mind a C2 means the installation has failed inspection and action is required and C3 will probably just get brushed under the carpet.

 

[suffolkspark]

What are you on about?

 

[Tunni]

Thought I'd made that clear. However... BS7671 requires cross sectional area of conductors to conform with 524.1. This boiler is wired in 0.75mm CSA cable, i.e the power circuit does not comply with the minimum 1.5mm requirement. Is this a C2 or C3? I can't decide.

 

[telectrix]

no code. 0.75 flex is perfectly OK as it's fused down at 3A.

 

[suffolkspark]

Thought I'd made that clear. However... BS7671 requires cross sectional area of conductors to conform with 524.1. This boiler is wired in 0.75mm CSA cable, i.e the power circuit does not comply with the minimum 1.5mm requirement. Is this a C2 or C3? I can't decide.

It's fine, no code as tel says.

 

[Tunni]

OK I understand the cable capacity and I understand the fuse, correctly chosen. What I do not understand is how this complies with BS7671 without a written risk assessment, not provided by the installer, clearly this is a "departure from regs" situation at the very least.

 

[DPG]

Thought I'd made that clear. However... BS7671 requires cross sectional area of conductors to conform with 524.1. This boiler is wired in 0.75mm CSA cable, i.e the power circuit does not comply with the minimum 1.5mm requirement. Is this a C2 or C3? I can't decide.

It's not a power circuit, it's basically an appliance cord.

Certainly not a C2 !!!

 

[James]

Can’t see a problem,
Flex to appliance should be at least the size of the manufacturers recommendation for the appliance.
What is the rating of the boiler?
Without that information it would be guess work to say that the flex is undersized.

 

[Tunni]

Worth noting too that this is a cable chosenby the installer and not a tail that was preinstalled by the manufacturer of the boiler.

 

[telectrix]

you could argue that the flex is not part of the fixed wiring, which ends at the FCU, therefore not to be considered on an EICR.

 

[DPG]

Worth noting too that this is a cable chosenby the installer and not a tail that was preinstalled by the manufacturer of the boiler.

Is it suitable for the current requirements of the boiler?

 

[James]

Agreed, @telectrix
It would fall under any requirements to pat test like any other appliance.

 

[Tunni]

My thoughts on the C2 were precisely that it would be a method by which the homeowner could apply leverage to get the plumber back to use a "better" cable. A C3 will most likely be ignored.
Recognising that in all fairness the installation is practically sound I guess a C2 is an overreaction perhaps. I still wonder about the fact that this is clearly a power circuit conductor, chosen by the installer and not compliant.

 

[telectrix]

My thoughts on the C2 were precisely that it would be a method by which the homeowner could apply leverage to get the plumber back to use a "better" cable. A C3 will most likely be ignored.
Recognising that in all fairness the installation is practically sound I guess a C2 is an overreaction perhaps. I still wonder about the fact that this is clearly a power circuit conductor, chosen by the installer and not compliant.

so consider this. a FCU connected to a socket (power) circuit with a 5A fuse to feed a light/s in 1.0mm T/E. for example in a shed/garage siruation. would youcode that?

 

[suffolkspark]

Mate you've been told it's no code. It's no code.

 

[Pretty Mouth]

OK I understand the cable capacity and I understand the fuse, correctly chosen. What I do not understand is how this complies with BS7671 without a written risk assessment, not provided by the installer, clearly this is a "departure from regs" situation at the very least.

Turn the page to P145. It says :

Non-sheathed and sheathed flexible cables - For a specific appliance - Copper - As specified in the product standard.

So whatever the manufacturer states as the minimum CSA, is fine.

 

[Tunni]

Thanks for the input folks. I think I will just add the observation of the CSA of the conductor to the cert and leave it at that.
I guess in some ways it's down to a perception of where a "power circuit" starts and ends. To my mind it is everything up to the point of the manufacturers' supplied equipment however I can see that as with everything EICR there are many ways to approach such things.
Not keen on 0.75mm flex though, regardless, in this kind of situation.

 

[suffolkspark]

Thanks for the input folks. I think I will just add the observation of the CSA of the conductor to the cert and leave it at that.
I guess in some ways it's down to a perception of where a "power circuit" starts and ends. To my mind it is everything up to the point of the manufacturers' supplied equipment however I can see that as with everything EICR there are many ways to approach such things.
Not keen on 0.75mm flex though, regardless, in this kind of situation.

Nooooo. You shouldn't even be noting it. It's perfectly compliant, please just stop ?

 

[Pretty Mouth]

May I be permitted to hijack this thread? Table 52.3 goes on to say:

Non-sheathed and sheathed flexible cables - For any other application - Copper - 0.75mm².

This appears to say that when flexible cable is used for any application (presumably that includes power circuits and lighting), a minimum 0.75mm can be used. What do you guys and girls make of that?

 

[Tunni]

so consider this. a FCU connected to a socket (power) circuit with a 5A fuse to feed a light/s in 1.0mm T/E. for example in a shed/garage siruation. would youcode that?

Come off it. This was a specific query. And I am grateful for the advice given. I remain unconvinced by the use of this particular flex however I am aware and have always been aware that electrically it is sound. My query regarded the application of a specific part of the regs and how people here would interpret that.