RCD tripping issue (again) - Earth Leakage?

[mikehammer69]

I agree. Originally I used banjo earth rings in the small above ground junction boxes and as you say, I bent them slightly. I had also used terminal blocks. As part of my checking and testing due to the latest RCD issue, I replaced all the banjo earth rings with piranha earthing nuts and the terminal blocks with wago connectors as it is faster to disconnect. I really like the British General junction boxes as they use plastic lugs to fix the lid to the box using a screwdriver, so no more rusty screws!

I have thought about replacing all the banjo earth nuts used on the wiring box with piranha nuts and filling in the screw holes, in an attempt to bring them into the box and make them water tight. Ideally, I would also like to use something like wago connectors instead of the terminal strips, but haven't found anything that can be "screwed" to the box. Maybe some sort of DIN rail setup is required!

On the box lids metal screws are better ime

Never seen an issue or rust whereas plastic cant be tightened as much and can give trouble

 

[Milleniumaire]

On the box lids metal screws are better ime

Never seen an issue or rust whereas plastic cant be tightened as much and can give trouble

Have you used these?

The fixings are integral to the box so simply require a flat head screwdriver to turn and release. Never had an issue with tightness. I've had plenty of rusty screws and there's always the issue of the screw dropping when being removed.

When I started having the recent RCD issues, I opened up an old junction box in which the screws were covered in rust and the banjo earth ring had rusted to the locking nut as both were metal. This box had been fixed too low to a wall, such that the SWA gland cover was touching the earth, so I assume moisture had risen up the cable and into the box and caused the rusting. One of the reasons I decided to switch to using brass piranha nuts.

 

[SUNRAY]

I also wonder about the way the metal protection of the SWA cables going into the wiring box has been done i.e. on the outside of the box, near the ground, which is wet meaning the outside banjo earth rings and internal earth connections could also get wet. As you can probably see from the latest addition of the outdoor socket, which enters the box on the right side, I connected the banjo earth ring up inside the box.

Personally I have never put the banjo on the outside as it makes no sense to me, When I did a SWA terminating course with Delta Cables about 50 years ago my thoughts were confirmed and not only that in those days a gland pack came with proper MI's and 2 brass nuts, the first clamped the gland into the enclosure and the second was used to clamp the banjo against the first- providing a secure electrical connexion to the gland and not relying on the mechanical security. IMO the banjo should never, never, be clamped against a plastic or other soft material inside or outside the enclosure as over time the plastic may compress or deform and the fitting will be loose.

Again going back to the older gland packs they came with a brass nut and bolt set and why anybody is stupid enough to use a ferrous fixing outside for an electrical connexion I have no idea. I love the piranha nut idea and have historically drilled and tapped a brass nut (even the gland body itself) to do exactly the same arrangement while attempting a failed gland repair and even suggested it to one of the wholesalers (Maybe they are available due to my suggestion )

Other than the space it occupies internally I don't know why people insist on using a brass gland when entering a non metallic enclosure when other fittings are more suitable.

Edit:
For internal to the enclosure use the SWA can enter using a stuffing gland then these;

Or in this instance when the electrical connexion the armour was not required/desirable (Actually in this particular job it resulted in a very dangerous situation);
Before

After

 

[Milleniumaire]

Other than the space it occupies internally I don't know why people insist on using a brass gland when entering a non metallic enclosure when other fittings are more suitable.

I only came across the IP68 plastic gland kits the other day and wish I had seen them earlier as I would have definitely used them over the brass gland kits, but to switch now would be a lot of work and expense and as long as the junction boxes are high enough off the floor moisture tends not to get into them via the gland/SWA cable so they seem to be good (for now at least).