Acceptability of chocolate block in backboxes?

[dom]

Some of my lighting circuits are complicated, e.g. external light switch for w.c.'s that control light and a single shared central fan extract.

This has necessitated jointing neutrals in the light switch back boxes, 3-way join in the first one I've done.

Neatest solution available to me is a bit of chocolate block (connector block). They're deep boxes, so I'm not struggling for space too much.

Is it regs compliant?

What's the best way to further protect it - self-amalgamating tape?

Is there a better solution?

[BruceB]

Yes it is acceptable. Add tape if you wish, secure if you wish.

NDQ29 Wago connectors or similar might be better

Regards Bruce

[John Rumm]

Yup. Connections like this require secondary overall protection - but the enclosure or back box provides this. Hence no need to tape.

There are alternatives - insulated crimps, and the various push in connection systems like wago, HT etc.

[Jim K]

plenty done by a "pro" in my recent refurb (no tape at all) so yes I reckon so

Cheers Jim K

[Owain]

I think terminals are not supposed to be supported by the conductor, so the connector block should be fixed to the box. I wouldn't bother for just one neutral, but if you had multiple ways it would be neater to fix the block to the box.

Tape is not required and just makes things messy.

Owain

[alexander.keys1]

It isn't essential to anchor a small terminal block, up to say 30 amps, providing the cable is not subject to strain, I've seen them widely used on conduit+singles surface installations, the blocks, always the porcelain variety, are placed in round conduit junction boxes. Of course it makes for a sounder job if you can bolt them down.

B&Q stock porcelain blocks, or you could use phenolic etc. if you can find them (hard black plastic, doesn't melt, can be cut with a hacksaw). The more common soft nylon 'choc-blocs', that come in strips of 12 that you cut to size with a Stanley knife, just don't seem as sound, there is the risk of the nylon melting if the connection overheats.

[The Natural Philosopher]

wot he sez, again. Good post. Covers all issues.

[js.b1]

Good quality high temp nylon glass filled terminal strips do exist.

1 - Double screw terminals. Both conductors pass right through the terminal block, so retained by both screws. Both conductors pass right through the terminal block from the same side, but you would need to use a square heatshrink cap over the terminal which I have not seen for a very long time (like a Pratley cap).

2 - Clipsal 56-series do interesting terminals. Plastic housing with a single cable entry hole at one end, shielded double brass screw terminal, peg at the other to supposedly push into the screw rebates on the 56-series backboxes. Black & green, take 3x

6mm and small sizes. Nicely made

3 - Pratley tube-with-grubscrew terminal & pushover cap. Require very large conductors, anything smaller slips past the grub screw.

Reminds me of two peeves of a DNO bod 1) terminal blocks should be screwed to the enclosure 2) terminal blocks should be cut with a proper tool because it otherwise reduces the insulation thickness around the terminals. A case of "if a tool is made it must be used", a bit like the crap SWA strippers - =A31.73 cost =A37-24 price tag. When I asked him whether he was as fussy over SWA glands, he answered yes but they rotted. I asked him why he used CW glands handing him one with a bit of SWA sticking out the bottom and poured water down the middle, through the armour gaps and all over his feet. Then handed him an E1W glands and walked off (it seals on the cable bedding also so moisture ingress into the enclosure can never get to the armour). He left at that point :-) Bastard had made up crap CW glands for me when I was 13 and I recognised him, they had rotted out leaving me a right tedious job digging up the cable around very expensive bamboo.

You can get insulated backboxes in flush versions - MK ESU/9/ML, the lug screw path is hidden from the box contents so you can never get a "earthed lug screw through neutral RCD trip". Plaster makes them as rigid as metal and the lug screw is a tapped brass strip.

Wago Lever are insulated, cable entry at one end only, cam operated conductor clamp. They are designed not to be clamped so there is little room for argument compared to a terminal strip with centre holes all along the middle.