Should we connect to this

[fattony]

Ok Im working on a large BBC site where there are about 10 3phase boards (hand made boards, mcb's on din rail) each board is backed up by a 250A switch fuse.

Basically there are 2 isolators in each board, essential circuitrs and non essential, there is a 70mm SWA supplying a 250A isolator in each board and they have linked out of the blue phase up to another 100A main switch for the non essential stuff.

The red and yellow phase are for the essential stuff, what they've done is instead of busbars they've run wires from the 250A isolator to feed the mcb's. However on the yellow phase the mcb's are indvidually wired back to the isolator in 4mm singles.

Im only working on the blue phase adding a couple of circuits, but should I connect them. My first reaction was im not connecting it but they insist I do and my boss agreed we would, but put in writing our concerns - Im not sure he's right on that?

They have agreed there are some issues regarding the boards but basically told me I have no right by law to stop the installation, I should connect the circuits then put my concerns in writing. If nothing gets resolved then I disconnect the circuit.

The maintenance electrician then said there's nothing wrong with feeding the mcb's from the main switch (100A) in 2.5mm singles as long as you don't have to much load

 

[breezer]

i dont agree with the maintenance guy.

your real problem is that you know what is right and wrong, and dont want to do what is wrong, when it ges pete tong guess who will get the blame for it?

your boss says you will do it because he has the job (and wants to get paid)

I think its a tough one, but i would refuse to do it point blank. you could also use the fact that a 2.5 cable is being protected by an over rated fuse as your argument.

 

[RF Lighting]

If you are not happy with the installation then you should refuse to connect to it.
If something goes wrong and you have been working on the installation, then it could well be your a**e that gets hauled up in court.

Also do not forget the EAW act.

Theoretically connecting each MCB direct to the main switch is OK, but I would think it could lead to problems, with all those wires into one terminal, but overloading shouldn't be an issue as you have have overcurent protection, albeit on the wrong end of the cable.

They have agreed there are some issues regarding the boards but basically told me I have no right by law to stop the installation, I should connect the circuits then put my concerns in writing. If nothing gets resolved then I disconnect the circuit.

I think you have every right not to connect if you feel it is unsafe. Check the EAW regs.

If you connect the circuits, and send your concerns in writing, I wonder if the letter will still be around when something goes wrong. Don't forget you will have to put your name on the bottom of the certificate.

Do you really think they will let you disconnect the circuit if nothing gets sorted? What timescale do you let them have to sort it out.

If you feel there really is an issue you could always involve the HSE, but surely an organisation has the funds and resources to get this resolved.

 

[baldelectrician]

if you or your company are enrolled with the NICEIC or ECA then you could ask one of their bods for a defenitife opinion in writing (email them some photos) and they will come down on your side of the opinion.

Then if it all goes boobs up- when you don't get paid when the job then you have 2 opinions when it goes to court.

 

[breezer]

but surely an organisation has the funds and resources to get this resolved.

dont you believe it.

you have not heard about / seen a bbc contract (you dont want to, I will say no more regarding contract) why do you suppose it is the way it is? its becuse it wont be paid for to be upgraded.

 

[fattony]

I dont agree with him either, people I've asked about this have called him all the names under the sun.

We're basically sub contractors so indirectly working for the BBC, we've done a few small jobs with this company before but when the BBC job fell behind they stopped payments from ALL other jobs until we got it back on track.

Harsh, but it worked we stayed over worked later and got it back up to speed my boss is now worried if he refuses to connect this (even under health and safety) they'll hold up payment, its only a small company and needs the cashflow. He's now saying we'll connect it, he'll put his name to it but inform them our concerns in writing - I dont think its right but we're in a corner.

 

[breezer]

I dont agree with him either, people I've asked about this have called him all the names under the sun.

We're basically sub contractors so indirectly working for the BBC, we've done a few small jobs with this company before but when the BBC job fell behind they stopped payments from ALL other jobs until we got it back on track.

Harsh, but it worked we stayed over worked later and got it back up to speed my boss is now worried if he refuses to connect this (even under health and safety) they'll hold up payment, its only a small company and needs the cashflow. He's now saying we'll connect it, he'll put his name to it but inform them our concerns in writing - I dont think its right but we're in a corner.

tell your boss, sorry, but dont work for the bbc ever again or any main bbc contractor. take the loss and run, its the safest option

 

[Pensdown]

Running individual cables from a mains switch to MCB's is common place in control panels and custom made DB's. It's the same principle as a bus bar chamber. As long as the cable that feeds the MCB is sized correctly for the MCB rating there is no problem. I can't work out from your post if the cables are 4 or 2.5mm? You also don't mention the MCB ratings.

But as RF pointed out, the problems are normally where all the cables connect to the mains switch and I've seen loads that have burnt out.

If the cables feeding the MCB's are undersized and your company did not supply the DB's then all you do is detail it on your test certificate.

 

[Lectrician]

if the cables don't loop via the mcb's, then I also see no problem. The short-circuit protection is there, but should be calc'ed. And the overload protection is there, downstream. The only thing is, the cables should be 4mm minimum and protected against damage (inside a CU is fine, although some panelboard makers sleeve the singles in tube!) if no short-circuit protection is offered.