Thread Rating:
  • 2 Vote(s) - 4.5 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Rcd or not rcd
#1
I am coming across a lot of consumer unit upgrades on some of my sites where they are fitting the new metal enclosures with dual rcd’s,Or in some cases an rcbo. None compliance??. I’m sure 5839 says not to be protected by an rcd or refer to 7671. I would of thought the only exception would be on a TT system?
I'm not the messiah,i'm a very naughty boy!!!
Reply
#2
25.2 i) The circuit supplying the fire detection and fire alarm system should not be protected by a residual current device unless this is necessary to conform to BS 7671. Where a residual current device is necessary for electrical safety, a fault on any other circuit or equipment in the building should not be capable of resulting in isolation of the supply to the fire detection and fire alarm system.

in other words don't have the fire alarm supply off an RCD
but we need to for BS 7671 compliance
OK then its got to be on its own RCD or an RCBO
www.fia.uk.com

Technical Manager FIA

All comments and views are mine own and may not reflect the views of FIA
Reply
#3
I thought rcd or rcbo was only required if special location (bathroom) or external light or socket or internal socket where an extension lead could be used externally or cable running through or over bathroom. So if none of the above apply and not TT then mcb will suffice?
P.s. hi Will, thanks for replying.
I'm not the messiah,i'm a very naughty boy!!!
Reply
#4
If its on its own RCBO then no issues.
Reply
#5
(10-06-2018, 02:05 PM)tc(two cup) Wrote: I thought rcd or rcbo was only required if special location (bathroom) or external light or socket or internal socket where an extension lead could be used externally or cable running through or over bathroom. So if none of the above apply and not TT then mcb will suffice?
P.s. hi Will, thanks for replying.

You are a little outdated there mate.

Generally, unless the cable is visible from dist board to fire panel, then it will need rcd or rcbo, the fire alarm circuit should be dedicated and not share an rcd with other circuits.


The vast majority of installs I go to, sparks has got it wrong. (shares rcd with other circuits).
Reply
#6
Actually the regs state that a fire alarm circuit needs no RCB or RCBO protection. Just a fault on any other circuit must not trip the fire alarm supply.
Reply
#7
If the cable is on show, surface run.

Im not saying because its a fire panel it needs rcd or rcbo, but if the cable is out of view, then rcd or rcbo needed.
Reply
#8
In BS7671, there is a specific exemption for fire alarms and extinguishing systems with regard to overload protection. Have a look at Reg 433.3.3(iv) and (v)
Reply


Forum Jump:


Users browsing this thread: 1 Guest(s)