rcd smoke circuit?

[Lee321]

hmmm conflicting views i feel

Nic say no rcd

discuss

 

[ianmacd]

Well that depends on if RCD is required to satisfy other requirements.

Maybe RCBO.

 

[Lee321]

such as?

cables buried at a depth <50mm? is not a requirement

 

[ianmacd]

WHy do you say that?

 

[Lee321]

WHy do you say that?

because other factors can override that regulation

 

[ianmacd]

Such as? You have made no argument for not rcd'ing them.

 

[Lee321]

an rcd need not be used on a safety service or even socket outlets (not including exclusion by way of trained persons)

 

[ianmacd]

Care to back up that with a regulation?

What about when a smoke is on a lighting circuit that serves a bathroom?

 

[Lee321]

Care to back up that with a regulation?What about when a smoke is on a lighting circuit that serves a bathroom?

yes. clearly the circuit will then need rcd before entry to bathroom

 

[ianmacd]

So why do you think that a cable burried <50mm does not need an rcd?

 

[Lee321]

So why do you think that a cable burried <50mm does not need an rcd?

when it is a safety service

 

[ianmacd]

Right well unless you start backing up your claims with regulation numbers then I think this thread will go no where.

 

[Couleddie]

560.7.1 Fire detection circuits must be supplied independently of other circuits and not protected by an Rcd protecting multiple circuits.

...but it does not say 'not protected by an RCD at all'

522.6.6

 

[kme]

Initial excerpt from BS5839-6

Although this doesn`t specifically mention the RCD part, it does provide definitive regulatory info on grade D power supplies:

15.5 Recommendations for power supplies for Grade D systems

The following recommendations are applicable.

a) The normal supply for smoke alarms and any heat alarms in a Grade D system should be derived from

the public electricity supply to the dwelling. The mains supply to the smoke alarms and heat alarms

should take the form of either:

i) an independent circuit at the dwelling

 

[Lee321]

hmm. so why is the nic saying that a supply to a fire alarm panel should be non rcd regardless?

 

[kme]

AH!

Although this technically only refers to grade E systems, I would still consider it pertinent:

c) The circuit serving the smoke alarm(s) and any heat alarms should preferably not be protected by any

residual current device (r.c.d.). If r.c.d. protection is required for reasons of electrical safety

(e.g. in an installation forming part of a TT system), either of the following conditions should be satisfied.

i) The r.c.d. should serve only the circuit supplying the smoke alarm(s) and heat alarms.

ii) The r.c.d. protection of a smoke alarm circuit should operate independently of any r.c.d. protection

​

for circuits supplying socket outlets or portable equipment.

 

[Apache]

hmm. so why is the nic saying that a supply to a fire alarm panel should be non rcd regardless?

Lostit - you seem to be looking for an argument?

Can you back up your claims with some kind of reference material?

Suddenly we have moved the goalposts and you are talking about fire alarm panels rather than smoke alarms.

Discussion is healthy (and the best bit of a forum such as this) but you need to give your side, or state why you disagree with it? Worst case go OT and entertain us. Single line, unreferenced posts are not a lot of help to man nor monkey.

What did you want to get out of this thread?

 

[ianmacd]

AH!Although this technically only refers to grade E systems, I would still consider it pertinent:

c) The circuit serving the smoke alarm(s) and any heat alarms should preferably not be protected by any

residual current device (r.c.d.). If r.c.d. protection is required for reasons of electrical safety

(e.g. in an installation forming part of a TT system), either of the following conditions should be satisfied.

i) The r.c.d. should serve only the circuit supplying the smoke alarm(s) and heat alarms.

ii) The r.c.d. protection of a smoke alarm circuit should operate independently of any r.c.d. protection

​

for circuits supplying socket outlets or portable equipment.

So put them on an RCBO as I suggested at the start.

 

[Jono Pashley]

I know lets all argue like whats been happening for the last few weeks....or not

/signout

 

[niceguy]

hmm. so why is the nic saying that a supply to a fire alarm panel should be non rcd regardless?

Since when did the NIC write the regs???

I cant believe there is yet another thread on this topic. headbang