Distribution box build

[AndyHill]

Just finished wiring distribution box but got a feeling something is a miss but cant work it out?!

 

[poni]

Connection the steel braiding of the SY cable to the earth bar? maybe the correct glands for the SY cable as well 

 

[Rob_the_rich]

neutral bar and earth bar both connected to box, therefore to each other?

 

[apprentice87]

Well.....

You got the three phases coming in yes??, they feed the isolator and then the 4 pole RCD.. So far so good..

You got the incoming neutral..  There does not have to be any means of isolating this [as long as it is not a TT supply OR domestic] but you can isolate it by means of the RCD which is better than nothing.. BUT, if it is TT, i would have thought that you would be wanting to isolate all live conductors at the one point, so a four pole isolator MIGHT be called for.

BUT and it is a rather big but.... It looks to me like you have the neutral bar connected to the backplate of the box, as is the Earth bar...

Now, i am only a welder, but this does not seem a very good idea to me soon as you load up any of the circuits the RCD will trip, AND if you lose the neutral, especially if you are on TT, switch any circuit on, and all exposed conductive parts will now be "live"

Also, what is the CSA of the cable you got leading from the RCD to the MCBS??? Is it sufficient for the total load as you got all the MCB's daisy chained together...

What earthing type you got???

john...

 

[Tony S]

Correct glands remove the need for earth pigtails in a steel enclosure.

 

[Andy™]

pretty much what everyone else said.. neutral looks like its on the steel backplate. SY braid does not looked earthed. busbar flex undersized. it looks like the sockets are fitted directly to the side of the enclosure, so why the SY? could have just used tri rated / 6491. personally, i would get rid of the TP isolator and use the RCD as the main switch. depending on use, maybe a 4 pole main switch feeding 2 RCD's would be better

 

[Sharpend]

Very neat, not sure very right? 

 

[AndyHill]

Just used the sy because it's just left over cable, not needed for any real reason. The neutral bar Is attached to the back plate(there is backing on it) wanted a plastic but and bolt but mite just take it all off and wrap some tape round it.

No idea what the earthing is its for out in Thailand and they have not given me any real data on that point. 

Its a 6 MM from the rcd to the mcb, I was thinking I mite need a 16mm same as the supply but wasn't to sure how big, even if I could get away with a 10mm.

 

[apprentice87]

Not being funny, but you do not guess at such things....

Neutral bar.. "wrap some tape round it????" That is a joke yes????  What you going to do when it kills someone????

john...

 

[Andy™]

 but mite just take it all off and wrap some tape round it.

 

[Sharpend]

Meeowwwwwch!!

hope they can't trace you! 

Think some more effort on design required. 

 

[AndyHill]

So thinking 16 MM to first mcb then. 

Yes it was a joke, not many ways to get the neutral pinned down apart from the way I suggested unless anyone knows another way?

 

[apprentice87]

Not sure what you meam by "neutral pinned down" Please explain?????

You need one of these..

http://www.directtradesupplies.co.uk/product.php/182369/gewiss-gw40401-insulated-neutral---earth-terminal-blocks-8-modules?gclid=CLH877ut0M0CFfgW0wodkqUAKQ

john...

 

[AndyHill]

Yes just a insulated terminal bar, it has slight think layer of plastic on the back, think they just bought them cheap, just so I don't have a neutral bar floating round in the box lol. So I can figure hat out and will have to have a proper look into what cables between the mcbs I need but think most of them will be alright, just worried about one going to 32a single and both 3phase. 

 

[Tony S]

50 to 1 this develops in to a "the RCD won’t hold thread".

 

[Sharpend]

its going to Thailand, do they have RCD out there? 

 

[apprentice87]

50 to 1 this develops in to a "the RCD won’t hold thread".

I think you might be right...

john..

 

[AndyHill]

Not a clue but it mite be used a few places so put it in. It's just got to go wherever the lads go to work. First time iv ever done anything like this, no drawings just some bits and bobs the old electrician got in. 

 

[Sidewinder]

So if this is going to be used in the UK, or in the EU, then you are going to CE mark it aren't you?

Simple answer for the N bar DIN rail terminals.

If you have an N-E link in the box, then it's a criminal offnce in the UK.

 

[AndyHill]

Ye so that rail needs sorting first, which I can do in the morning. 

I thought ce mark was just for things being sold? this is just an in house build. 

Only other thing is the cable sizing, anyone done anything like it before?