Storage heaters

[sjl468]

Hi.
Just been to a flat that needs a new CU. It's got three storage heaters fed from three 16A MCB's within the main CU. The output of these MCB's are fed into a 3 pole contactor which feeds the heaters. The contactor is operated via a FCU which in turn is fed from a multi-output Meter. So the contactor is only turned on at off-peak hours thus only allowing power to the heaters between these times.
The supply to operate the contactor has no RCD protection. It is simply a 1.5mm cable from the meter to the contactor via a FCU. It's a PME system and all the other flats are wired up this way. The flats are about 10 years old. Is this ok? If not I suppose I could just replace the FCU with a RCD FCU? Any thoughts?

 

[RF Lighting]

Does the circuit require RCD protection?

 

[sjl468]

That was the question. It is a PME and as long as the Ze is low some circuits don't have to be RCD protected such as smoke alarms. But I'm a bit confused as to a supply coming straight from the meter via a FCU, which incidently, is outside in the meter box! With a 13A fuse.

 

[londonboy]

Is this cable buried in the wall?

 

[RF Lighting]

You are the one that has seen the job.

Are you sure you are competent to be doing this work?

 

[londonboy]

Thats what I was thinking, reguarding the comments about smoke alarms and low ze

 

[sjl468]

The meter is the other side of the wall and the cable goes straight through the wall to the CU.

 

[RF Lighting]

Have a look at regulation 522.6.6 in BS7671 and tell us which part you think would require your circuit to have RCD protection

 

[sjl468]

So you don't know.
Can anyone else shed a bit of light on this for me please? Just never come across this before.

 

[RF Lighting]

You are the one that has seen the installation, so it is up to you to work out wether the circuit requires RCD protection or not.

Which part of regulation 522.6.6 makes you think it does?

 

[Aragorn84]

Presumably he does know, but is asking you to read regulations that you should have to hand but dont seem to...

 

[sjl468]

It doesn't. Just wanted some other peoples point of view that's all.
Like I said it's something i've not come across and don't want to get it wrong.
Cheers.