Works of Art or Spare Cable within CUs/DBs?

[JohnW2]

What I see inside CUs/DBs these days tends to fall into one of three categories. The first are the 'orrible messes, sometimes incorrectly wired, and I'll say no more about them. Of the remainder, some are beautifully neat, but with the consequence that there is little, if any, spare cable available should re-termination ever become necessary, whilst in the final category, some spare cables has been kept available ('just in case'), with an inevitable reduction in the aesthetic beauty of the sight!

I wonder what people feel about the pros and cons of those two approaches. In the past, a CU's internal wiring was often 'left alone' (apart perhaps from the occasional tightening of screws) for the entire life of the installation, but modern testing requirements involve quite a bit of 'tampering' with the connections, which I imagine sometimes leads to the need to 'trim back and re-terminate'.

Kind Regards, John.

 

[echoes]

I tend to bend the CPC & neutral wires in a gentle 'U' shape behind the MCBs so they go up vertically into the neutral / earth bars. The line wires are the same, but then bend down into the MCBs. Then everything is nice and neat but I have a few cm of slack in case a re-termination needed. I don't use cable ties.

A bit of thought about the placement of cables and the ordering of the breakers helps loads.

 

[ricicle]

It is nice to dress cables in a DB and a domestic board with (mainly) solid conductors shouldn't be a problem as they will more or less stay where they are put. Ties can be frowned upon due to grouping but in a domestic CU this is unlikely to be a problem.
A larger commerical/industrial board is a bit more involved as they can tend to be stranded singles which do not stay where put and ties are a no-no as the circuits could all possibly be at or near full load.

 

[JohnW2]

I tend to bend the CPC & neutral wires in a gentle 'U' shape behind the MCBs so they go up vertically into the neutral / earth bars. The line wires are the same, but then bend down into the MCBs. Then everything is nice and neat but I have a few cm of slack in case a re-termination needed. I don't use cable ties.

Yes, that would seem to me to be the best compromise, and is essentially the third of the approaches to which I referred. It can, however, get a bit difficult to get loops neatly behind the MCBs in a busy board with a lot of the cables coming from below.

A bit of thought about the placement of cables and the ordering of the breakers helps loads.

Indeed so, and that's probably the factor most able to affect neatness (or the lack of it).

Kind Regards, John.

 

[sherlockholmes]

I had a cu installed yesterday, didn't look like much spare on the incoming cables, but plenty of swirly whirly cable (technical term) on the rcbos. The whole thing would not have looked out of place in the Tate, almost a shame it has a cover on now.

 

[JohnW2]

I had a cu installed yesterday, didn't look like much spare on the incoming cables, but plenty of swirly whirly cable (technical term) on the rcbos. The whole thing would not have looked out of place in the Tate, almost a shame it has a cover on now.

Indeed. However, there is a need to find a compromise between beauty and the ability to reterminate a cable without have to replace or extend it. It sounds as if your electrician is towards the beauty side of that spectrum

Kind Regards, John

 

[TicklyT]

When terminating large telecommunications cables of 100 pair or so, it was common practise to cable tie a few pieces of plastic conduit across the box to form the wiring round. When the conduit was removed afterwards it left neatly formed bends and a few centimetres of spare length in each wire.