Church Wiring

[The Colonel]

I have been approached by an electrician who is quoting for some work in a church and is baffeled by some of their specifications and I would be grateful if anyone can help.

It is necesary to install a new sub circuit into a boiler room to feed a gas boiler, pumps etc, the electrician is happy with normal 6mm cable but the church has specified either fire safe cable or mineral insulated copper cable or FP2000 all of which carry considerable extra cost for what would appear to be no extra benifit.

Not sure of the denomination of the church but the spec seems to have come from their area office or advisor, if anyone has any usefull input it would be welcome and may save them quite a bit of money.

Thanks

The Colonel

[Graeme]

They may think as it a boiler room it has to be fire rated cable or it could be an insurance thing.

FP200 only goes to 4.0mm from memory

[John Webb]

The reason for the specification, particularly of MICC cable, is to minimise intrusion of the cable both visually and through the fabric. IE it does not need conduit, surface-mounted or chased into the fabric to conceal said conduit, or large holes drilled through the fabric.
The reasons for this are to minimise irreplaceable disruption of the fabric in what may be an ancient and listed building. There is a booklet 'Wiring in Churches' published by the Council for the Care of Churches - see www.ccc.c-of-e.org.uk - which explains much of the needs of churches regarding electrical installations.

It is possible that the reference to FP200 etc is a misunderstanding related to the booklet's chapter on fire-alarm system wiring.

The electrician's reference to 'area office or adviser' suggests this may be an Anglican church and the Diocesan Advisory Committee are involved in giving authority for the works, as they have to by law.

Hope the above is of help.

[The Colonel]

John

Thanks for the info I will pass it on, I was hoping that you would spot this one and give me the benifit of your knowkedge

[John Webb]

My pleasure. I did have a copy of the booklet but cannot find it at the moment. I think it may be under revision currently as well from recent correspondence within my own Diocese.

If the electrician can find a relatively short run from the Distribution board to existing ducting or trunking leading to the boiler room, then more ordinary and cheaper cabling techniques might be acceptable if it is only visible for a few metres.

[Goodsparks]

As well as the intrusion / install properties, MICC or FP200 were probably specified because of their LSOH emissions. If this was the case, a fire- safe, cable could be installed rather than a fire resistant cable. These could include Pirelli LSX or Batt cables guardian range. Both are available upto 6mm2, the guardian range is is the only one also available in black. All of the above are round in construction and have a metalic screen, which enables the cable to be "dressed" and remain in shape around features within the structure unlike pvc twin and cpc cables.

The other thing to bear in mind is that most commercial wiring specs call for a full size CPC, Flat Twin and CPC (housebashers) cables are unable to meet this requirement as the CPC is always one size smaller than the live conductors.

Paul

[Graeme]

why don't they use the "power of God" to supply the boiler?

[wee brian]

LD0H - fire safe - be carefull you dont fall for the sales patter.

Most low smoke cables burn more efficiently - thats why you get less smoke

[John Webb]

I've managed to dig up some more information. The 'Wiring for churches' was first published in 1981 as part of a booklet on Lighting and Wiring.
This allowed four cable systems: MICC, cables drawn into steel conduit or trunking, cables drawn into heavy gauge high-impact plastic conduit or limited use of PVC insulated and sheathed cables in specific circumstances.
The booklet was rewritten by a new author to deal solely with wiring and recommended only the use of MICC.

SPAB (Soc for the Protection of Ancient Buildings) published a technical Pamplet 9 on 'Electrical Installations in Old Buildings' in 1985. This mentions PVC insulated & sheathed, MICC and Steel Wire Armoured PVC (SWA) cable.

The question has been raised about the use of FP200, Firetuf etc as allowable and cheaper substitutes for expensive MICC. But it has been pointed out that these cables still need mechanical protection just as PVC insulated/sheathed needs protection as required by the IEE Wiring Regs (BS 7671).

The question of what electrical systems to deploy in churches is of some importance as churches improve lighting, heating and audio-visual systems. The cost of MICC might put off some churches from renewals if it is the only system they are allowed to use, resulting in the retention of elderly systems with the potential for shock and fire hazards.

In my own church when we renewed our lighting system we thought we could lay PVC T&E across the rafters in the roof space without mechanical protection, as allowed in BS 7671. After a year we had to trunk it all up because squirrels were sharpening their teeth on the cables! So not even BS 7671 covers every potential harm to cables.

[The Colonel]

Thanks for all the info and especialy John, I shall pass it onto the sparks in the knowledge that he knows more about the technical bits than I do, i'll stick to risk assessments