Hi, A friend just had a new metal CU installed and have two questions on the way it was installed. The unit is a metal wylex which is fire rated. 1. The large knock out at the back where all the cables go in the unit is not sealed in any way. Does this not mean the fire ratimg is lost? 2. Two wooden battens we used to mount the unit on the wall (left and right). This means you can get your hand in the unit from the top and bottom. My question is whether the above points need addressing and how. Also would an installation like that be ok accusing to the latest regs? My suggestion is to mount the unit on the wall directly. This way although the unit will still have the cut out for the cables at the back, it will be flush against the wall, sealed around with fire rated silicon. Also remove the tails from the bottom and refit them from the same holes using fire rated grommets. Thank you for the replies!
It is not supposed to be IP68 lol. It requires IP4x top and bottom and Ip2X sides, there is not rating for the back. As for mounting the consumer unit on wooden battens this is a not professional and is bad practice. You should not fasten the CU onto wooden battens, you can however fasten it to a specific fire self extinguishing fibre board. It is for sure better to fasten it to the wall directly with the least amount of combustible material in the vicinity of the CU. The CU is not a FD30 fire door lol you don't need fire intumescent sealant or high temp sealant around the CU. Here is an example of retaining the IP4X rating with cables entering the top of the CU using trunking and threaded glands nutting the trunking through the CU punch outs and allowing cables to enter.
Wylex do a mounting frame to allow for rear entry with surface mounted cables. They should have used one of these, not batten.
While I would agree there is no IP rating for the back, I would expect that the argument of it being flush to a wall is expected. If its battened off the wall and you can therefore get your hand in the hole I would suggest this is wrong. It should be at least IP2X to minimise the risk of inadvertently sticking your finger in the hole. It would take 5 minutes to cover the top and I presume bottom openings
Hi all, Thank you for your replies. I think after reading all you had to say, I think the best thing to advice my friend is to ask the electrician to ensure there is no way to get your fingers in the cu, ie fix either on the wall or on a board, instead of battens ... Or add a conduit / extra battens on top and bottom. Thanks again for the very useful replies!
Meet the CU Pattress, If you want to retain the surface cables through rear entry on the consumer unit then it can be done properly by the use of a Consumer Unit pattress backing plate like this.
Retrospectively fiting a new Wylex patress will mean a re-install of the consumer unit, with re-test of all circuits. If there's real concern then just seal the void with intumescent sealant. that will achieve safety for those who have triple jonted 12" fingers and provide additional fire sealant when the consumer unit catches fire. This can occur almost daily, you can't be too careful. PS There's a company that sells the stuff FlewFix or something, can't remember the name, off hand..
Yea i used them a couple of times, they only cost around £35 and look very tidy and make it easy to work with when pulling in the cables.
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