Glanding 3 phase into metal distribution board.

[-Matt]

Quick question, have a small caravan site to wire up.

Have 3 phase supply and TT earthing, 30ma RCD in each individual pods.

Was planning on using a 100ma type S incomer in the main DB to protect the sub feeds. ( this should stop a dodgy caravan tripping the whole site being 100ma time delay).

However not overly familiar with TT and 3 phase in terms of protecting the tails.

Ive been told by my niceic assessor with single phase and metal consumer unit, it is fine to just use the special stuffing glands.

However i dont think they make them for 3 phase?

So how would you do this?

Or would it be best to just get a seperate insulated board to house the RCD and then main switch in the DB?

Anyone any advice on this?

 

[Pete999]

If you are slotting a steel enclosure to enable phases to enter through separate routes, whether by bush gland or whatever, if you use a steel locknut then you have negated the point of slotting the steel plate in the first place, as you will be magnetically bridging the slot from either side. Where slots are made for this purpose then brass fittings - either side, would be favourite.

Use a plastic stuffing gland then

 

[davesparks]

Steve, I respect your thoughts, but disagree, experience tells me, although theoretically it works, practically and experience tells me it's a No, sorry Mate.

He’s right, steel locknuts will magnetically join the two sides of a slot in a steel gland plate.
Tony who used to frequent this forum has a good story of contractors using steel locknuts for glands transformer tails and it causing eddy current problems.

 

[Pete999]

If you are slotting a steel enclosure to enable phases to enter through separate routes, whether by bush gland or whatever, if you use a steel locknut then you have negated the point of slotting the steel plate in the first place, as you will be magnetically bridging the slot from either side. Where slots are made for this purpose then brass fittings - either side, would be favourite.

Use a plastic stuffing gland then

Steve, I respect your thoughts, but disagree, experience tells me, although theoretically it works, practically and experience tells me it's a No, sorry Mate.

3 dislikes from 3 respected guys, made me rethink, I reread and reread the post and came to the conclusion that I was wrong, so I humbly retract my thoughts.

 

[Pete999]

If you are slotting a steel enclosure to enable phases to enter through separate routes, whether by bush gland or whatever, if you use a steel locknut then you have negated the point of slotting the steel plate in the first place, as you will be magnetically bridging the slot from either side. Where slots are made for this purpose then brass fittings - either side, would be favourite.

Use a plastic stuffing gland then

Steve, I respect your thoughts, but disagree, experience tells me, although theoretically it works, practically and experience tells me it's a No, sorry Mate.

3 dislikes from 3 respected guys, made me rethink, I reread and reread the post and came to the conclusion that I was wrong, so I humbly retract my thoughts. Still reckon a plastic stuffing gland would be the answer.

 

[RWJ]

Tony who used to frequent this forum has a good story of contractors using steel locknuts for glands transformer tails and it causing eddy current problems.

I miss Tony and his vast knowledge, I used to look after his GIF animations. Shame he decided to go the other route when Ben's forum closed.

Anyway back on topic!!!!

 

[Bobster]

I miss Tony and his vast knowledge, I used to look after his GIF animations. Shame he decided to go the other route when Ben's forum closed.

Anyway back on topic!!!!

He did come back on here for a while, but then was banned again for disagreeing with a moderator.

 

[Pete999]

If you are slotting a steel enclosure to enable phases to enter through separate routes, whether by bush gland or whatever, if you use a steel locknut then you have negated the point of slotting the steel plate in the first place, as you will be magnetically bridging the slot from either side. Where slots are made for this purpose then brass fittings - either side, would be favourite.

I realise it was a while ago you disagreed with me Steve, but the single core conductor you are using to enter the enclosure, would that be a Single insulated with a PVC outer covering, yes, then why bother with a lock nut and bush? use a PVC stuffing gland, why would you bother using an SWA type gland for a single PVC/PVC/ single cable. Or if it's entry via a run of trunking, a plastic bush and lock ring would suffice, as I said sorry for the lateness of my resonse, just been running through past postings, have a nice day, or whats left of it.

 

[RWJ]

He did come back on here for a while, but then was banned again for disagreeing with a moderator.

Banned or password and email address changed as happened to me when I corrected the ex "Global Mod" mentioned in my last post!!

 

[Pete999]

Banned or password and email address changed as happened to me when I corrected the ex "Global Mod" mentioned in my last post!!

Oh right RWJ thanks for the heads up, I was going to add, just to justify my post, my response was based on single PVC/PVC or just PVC singles, I will add that if I was using single core SWA then I would go to the extent of utilising a Nonferrous cable entry plate, pity he is not about to clarify our disagreement.

 

[Pete999]

Oh right RWJ thanks for the heads up, I was going to add, just to justify my post, my response was based on single PVC/PVC or just PVC singles, I will add that if I was using single core SWA then I would go to the extent of utilising a Nonferrous cable entry plate, pity he is not about to clarify our disagreement.

 

[stevethesparks]

Hi Pete,
I was just making a point that if a steel trunking/enclosure was slotted to allow P&N or PPP&N to enter through different holes - if a gland were used (and at the time I had assumed a brass stuffing gland ref posts #6, 8, 9) then a brass lock-nut should also be used.
I wouldn't contemplate an swa gland as phases nor P&N can be run through separate armoureds. Micc, that's a different thing.
Plastic gland and bush is fine with me.

 

[Pete999]

Hi Pete,
I was just making a point that if a steel trunking/enclosure was slotted to allow P&N or PPP&N to enter through different holes - if a gland were used (and at the time I had assumed a brass stuffing gland ref post #6) then a brass lock-nut should also be used.
I wouldn't contemplate an swa gland as phases nor P&N can be run through separate armoureds. Micc, that's a different thing.
Plastic gland and bush is fine with me.

Yeah I agree with you, think we got ourselves into a bit of a pickle over who meant what and where, till glad we got that little misunderstanding
cleared up, surprising how things can get misconstrued. Like I said have a nice rest of the day.

 

[stevethesparks]

And you

 

[Nigel]

I agree with your NICEIC assesor.

No issue with using the gland at all and keeping any enclosure metal.

Personally I would also install trunking to afford the cables coming straight out of the DNO meter protection also until they are made off into the DB or RCD enclosure.

 

[Pete999]

I agree with your NICEIC assesor.

No issue with using the gland at all and keeping any enclosure metal.

Personally I would also install trunking to afford the cables coming straight out of the DNO meter protection also until they are made off into the DB or RCD enclosure.

Pardon? can you be a little bit clearer please don't quite understand your statement.