Discuss 3phase industrial - clear a couple of things up? in the Commercial Electrical Advice area at ElectriciansForums.net

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screech

Hey guys, first post here so please go easy :)

Iv just started this job, helping a mate of mine, whose mate has brought a unit that needs fitting out.

Il try and paint a picture for you...

Its the middle of 3 units, that was knocked into 1, but now been bricked back up into 3...

Apparently it was all wired as one so when they bricked it up they just cut through it all.

Its had a new supply put in, and a 6way 3phase proteus board put in.

Above the ceiling i found a coiled up 16mm T+E that went off to a Single phase 6way board that feeds the upstairs warehouse lighting and the small office lighting and power.

Off the 3phase board comes one 6a mcb feeding the downstairs warehouse lighting (Grid ceiling with flexed lights)

He wants a load of power put in downstairs around the warehouse, a few sockets upstairs, roller shutter powered up at the other end of the unit (55m run) and the unstairs office area lighting will need re-wiring as the asbestos ceiling is going to be ripped out!

Now just want to clear a couple of things up, if possible.

Does everything have to be RCD protected. As its a 3 phase board i dont want to just put an RCD mainswitch in because of lighting!
Im thinking of putting RCBOs on everything, but obviously that the more expensive way of doing it.

I dont really touch on industrial much, and when we do the lighting doesn't get RCD'd, but in my understanding, isn't that wrong?


What would you do?
Ohh dear, sorry i seem to have written quite a lot there! Thanks for reading and i hope you can give some ideas.

Cheers
 
Rcd protection is only required if cables are hidden below building surface materials and not mechanically protected but usually industrial is surface steel conduits or trunking thus rcd wouldn't be required so it depends on installation methods
 
Thanks for the quick response.

Cables will be clipped above the susspended ceiling, then dropped down in tube to the outlets.

To get the the upstairs office area existing cables go up a boxing.

The 3phase roller shutter is going to be swa cleated along above the ceiling also.

Thanks for the advice :)
 
Thanks for the quick response.

Cables will be clipped above the susspended ceiling, then dropped down in tube to the outlets.

To get the the upstairs office area existing cables go up a boxing.

The 3phase roller shutter is going to be swa cleated along above the ceiling also.

Thanks for the advice :)
Just remember if any wires are unprotected in the offices under plaster then rcd protectection is needed so check the wiring to the switches and also metal capping wont suffice as protection.
 
I will be rcd'ing all socket outlets anyway.

Don't see why I need to on the roller shutter?

Everything in the toilets will be.

So it's just the lights, it's all stud wall, but il come down surface in tube then I'm all good.


Cheers :)
 
Thats what i thought.
Just been to get the breakers, didn't realise how expensive RCBos are!!!

Iv decided to change the single phase CU to a duel split load, that way i can run the cables up how i like and put the switch drops in the stud wall. If he doesn't want to pay for that then will he want to see loads of tube!!

cheers

Well just been there again and had another look above the susspended ceiling, clipping up there is going to be inpossible, its all criss cross metal work!

Dont think i wanna just throw cable above there, gonna have to have a think on that one!
 
Last edited by a moderator:
Run them in some cable tray or basket.
 
Hi fellas. First of all, what a great site! Found it just through a google search!

I am an apprentice working for a firm in Sussex.

This topic is similar to the job i have been put on this week.

The electrician and i have been given the task of wiring some lighting and power supplies in an office.

The office has a false ceiling, the 600x600 grid type.

We have been told to throw the cables over the grid, no tray or anything (theres nothing really up there to tie or fix anything to anyway!)

I was just a little concerned about this, not that its my problem, im just learning, but is this in any way against the rules/regs??

Many thanks.
 
I'd only rcd the sockets, tray and basket / swa / run FP200 or equiv. on tray above offices to lighting mashalling boxes , flex out to luminaires don't forget the em's
 
Hi, thanks for the reply!

Yes the sockers are down to be on RCD.

We've been given T+E to wire to everything, to boxes for lights where flexes will be brought out of, and to where the socket drops are, will enter tube.


thanks
 
Thats what i thought would be said tbh. I cant have a say in this, im 'just the apprentice. (lol!)'

As far as i can tell, they are just planning on having the T+Es laying above the grid ceiling. Id say its commercial? Office areas, with 600x600 drop in fittings. And a small workshop (no idea what they do, something with sewing machines!)

My manager is not the type of person i want to question, which is why im just getting ideas here, then maybe il confront him!

Il ask at college too!
thanks for your comments
 
I know, its going to look shocking! Im glad its not my name going on any paperwork!!

So to answer my original question, is it against any regs to do it this way??

thanks.
 
Well I'm sure if you paw through selection and erection, protection of cables, etc etc etc you will come to the conclusion ( the picture im painting of it anyway) is yes.)
You never know his term chuck em over the ceiling might mean cable tied to 50mm suspended tray
 
Hi guys.

Well i decided to ask him today, as im always told that asking questions is a good thing!(?)

He made it very clear that just laying the cables on the grid is the idea, and that is the way it can be done. I asked what about the regs on containing them and he said theres no problem here.

I havn't got any books as yet, but i will be asking at college on friday.

Regards.
 
there's no problem as far as that's concerned. it's not pretty, but it's not wrong

the cable is adequately supported (by the false ceiling) and the unfortunate part of it is, they can throw JB's wherever they like as it's considered accessible for inspection and maintenance
 

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