Wiska box, not much better than the Toolstation on, how should one do this?

Apr 20, 2025 Last reply: 1 year ago 4 Replies

This continues from the "How to remove knockouts....." thread. I'm beginning to think I must be incompetant or something but I've never had so much trouble before with a relatively simple requirement.



I now have a Wiska outdoor box and their spring earth clips.



The knockouts work! That's one improvement on the Toolstation box. Simply screwing a gland into a hole in the box pushes the knockout out, so that's one hurdle overcome.



However, it's all downhill from here on.



This is a replacement box, the old one got damaged, so the wires are already in place and can't be moved much as they disappear into the ground. So this produces problem one, you have to remove the gland from the SWA, screw the gland into the box and then re-do the SWA clamping into the gland. It's possible but it's not easy, I'm just glad the weather is reasonably warm. It would be much easier to terminate the cables first and then fix them into the box with a nut. I think maybe I'll have to do this, but see below.



Then on to the Wiska 'Earthing Springs':-



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It sounds a wonderful idea but it doesn't really work. With standard M20 glands there really isn't enough thread exposed to clip the spring on, it's also well-nigh impossible to actually do it because squeezing the eylets doesn't open the spring enough to clip on, it opens on the skew and just doesn't work. If there was a lot of thread exposed it might be possible but in reality it doesn't. I'm also not at all convinced about the long-term security of such a connection, I don't think I want to rely on it.


So, back to square one, how to replace an outdoor connection box with three M20 SWA glands into it? I think I need to go back to a plain box without threaded holes as one can then secure the glands with a nut **after** fixing the gland onto the cable. However that raises a couple of issues:-



Can one get brass 20mm washers for the glands, and brass nuts? The ones I took apart from the old broken box were steel and very corroded.



How to tighten the nuts given the limited accessibility, I guess a custom made box spanner - short box with a handle - might be the best answer.



Any/all advice (and sympathy) welcome! :-)


Would a Wiska Piranha nut work?

Yes, probably, but I think the 'Essentials' nuts from Screwfix would actually be better:-

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As several comments say, they are expensive, but they solve most of the problems connecting SWA into a box. I hope the screws aren't steel!!

ok good start...

Not tried those so can't comment.

Yup, when all the wires are fixed length, it can be difficult trying to do too many jobs at once. I would fit the glands to the SWA, then fit the glads to the box, then fix the box, and lastly wire it up. That makes it easier to work with shorter lengths of SWA, and only fight one at a time. Fixing the box after attaching the glands allows a bit more wiggle room if necessary.

The supplied banjo tags are IME normally non ferrous - although not as shiny and bright as the brass glands themselves.

The thin backnuts are usually steel though. That matters a bit less since they are there for clamping force rather that electrical connection.

There is a variation of the bush spanner that will fit over the backnuts:

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Go with a plain unthreaded box, bin the backnuts and banjo tags, and use Piranha nuts or similar:

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Here is one I needed to put back in place with three of the 4 SWA fixed in length (but new glands)... Turns out I had one fewer Piranha nut in stock than I thought - hence the banjo tag used on one!

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[snip me moaning]

Thanks John, really useful all that.

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