phantom9

Posts: 1757
Joined: 16 December 2002
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Good morning Richard
There is no specification required to build an enclosure around a fuse board. The regulation makes reference to "enclosed in a cabinet or enclosure that is constructed of non-combustible, or not readily combustible, material." My concern is that focus at the moment is on the CU itself. Much of the debate is centred on a metal CU. No mention of metal in the reg it is one possible solution of many. I think another fault with this industry is preoccupation with minute detail and fanciful what ifs. As I type this, someone somewhere has just been killed in a car accident. I doubt very much that a CU has just caught fire. Put things in perspective. The likelihood of a fire is relatively low. The intention, surely, of the reg is to limit the spread of fire, not contain it or eliminate the fire indefinitely or make it fire proof. Modern building materials are not readily combustible. Plasterboard is one example. Architects and structural engineers will have just as much responsibility towards improved fire safety as electricians will and they will have more ability to come up with cabinet solutions for new-build housing construction in conjunction with electrical designers. Fire safety around electrical equipment is not just an electrical issue as this debate would seem to imply.
The fire safety aspect is not intrinsically an electrical issue. The consequence of a fault in wiring can result in fire but the integral issue with ELECTRICAL safety is good design and good workmanship. Consider that cable sheath burns. The electrical energy contained within insulation and cable is all run in combustible material. The consequence of a short circuit or an overload causes heat and possibly fire. In a domestic situation (the reg is specific to domestic) it has been decided that one aspect of fires can be improved by consideration of the materials used in the installation. Pretty much all components, including cable insualtion are all combustible materials. So they are going to catch fire and burn whether the CU is metal, rock, stone, gold, silver or cape durasteel 4hr fire board. The componets will burn. So it is absurd to look at this problem from an electical viewpoint and expect all of it to be solved by using a metal CU. Too much focus on 2metal CU" and not enough thought on the reg. Coding the CU as a C3, which is apparently already decided, is typical of how the trade operates. Rote. Do you also code the cupboard where the fuse board is located? It is one of the options and mentioned in the reg. Conveniently missed? Do you code the switch gear that serves it? The reg includes switchgear. The reg includes either/or scenarios not just "the CU must be metal". WRONG! Forget metal. If metal is what the manufacturers want to use then fine, it is not up to us as electricians to decide that metal is the only consideration. The reg doesn't make reference to metal, only non-combustible.
I put a hell of a lot of thought in to things like this I don't just knee jerk react to a proposal. The electric media have already made the mistake of focusing on 'metal' fuseboards and that in itself misinforms the trade.
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