Identifying MCCB's

[shanky887614]

Ok so it's been confirmed, there are no previous records what so ever to refer to.

This is now a case of agreeing how I'm to go about a full test and inspection and what limitations I can agree with the client.

I'm going to suggest live testing only on all sub main supply's and anything that can't be disconnected due to production. Will this be enough to cover myself if anything was to happen after my signature goes on the whole installation?

After looking further into a few circuits coming from the main panel there are some seriously worrying things I've seen which wouldn't suprise me as to why there isn't any certs.

They have 2 lines of 6 industrial microwaves supplied from 250A IEC 60269-1 fuses straight from the main panel in 70mm SWA. That only just meets the requirements of the current carrying capacity by 1 amp and that's assuming they are laid on the tray without being bunched the whole way to the final points.

Even worse than that is that the fuses in the main panel compartments have been bodged in as the panel has been designed to isolate MCCB's.

They then go straight to the microwaves and don't have any isolators what so ever meaning the only way to disconnect them is to turn off the whole installation.

I know this is serious, and I know it needs to be sorted but the firm seem to be very tight in regards to any situation big or small (Irish run firm!).

I really need the work because I've not long set up so I need to approach this cautiously.

How would any of you more experienced sparks go about this?

tell them straight up.

do you want me to carry on with the testing, the boards and supplies to the machines dont comply.

im guessing there are no emergency stops etc either judging by what your saying.

you could argue due to derating factors the cable is not satisfactory and they should get the original contractors back to bring it upto the required specification at there cost.


its upto you how you want to go from here, personally all industrial should have some form of local isolation.


surely having to isolate the plant just to work on one machine is ridiculous especially in production.

 

[bossian]

Can of worms comes to mind......

How can an installation of this size have no records?

 

[moosey86]

I spoke to the NIC about the microwaves (they're actually called transmitters) and they said as long as it's heavily labelled and people made aware what the set up is that's the best I can do without a complete re-design.

As for the cable and fuse size I didn't realise there are isolators inside the transmitters which have their own fuse carriers. I would prefer them to be on the outside but at least I can get to these fuses and drop them down to 200A from 250A. That solves that problem.

Just a quick question on another aspect of the testing.....

The cabling used throughout is predominantly NYY-J. Horrible stuff to work with but I can't imagine it being cheap either!

Question is, type of wiring code? I've been putting A but I did think of using other. If you look at the specs it is PVC/PVC, just not the sort you'd expect if you were to go through the sheets without looking at the install. Not sure about current carrying capacity though, I've been going by standard PVC/PVC so far.

And yes bossian, can of worms indeed! But it's on a day rate so the worms can stay in the can unopened for the time being [emoji4]

 

[Richard Burns]

You initially stated you were doing an EICR and then you have mentioned that you can change the fuse sizes, this is not part of an EICR.
I would concentrate on the inspection and testing and consider the options for repairs at a later date.
The state of the installation you describe means that any repairs would have to be very wide ranging in nature and possibly require significant changes to the supply methods, layout and protection. I could foresee that since they cannot make any accommodation for you in the inspection and testing they will not make any accommodation in terms of repairs either so do not get ahead of yourself just yet.

NYY-J cable is PVC PVC cable and since this section is an irrelevant part introduced by the NICEIC do not worry about it, PVC PVC is correct and using the standard PVC PVC tables will be acceptable for current carrying capacity. Any variation is likely to be of a matter of an amp or two and would vary by manufacturer, though most of them use the BS7671 tables anyway.

 

[moosey86]

Cheers Richard, the chief engineer said he wants the observations sorting as I go along. It's all on a day rate so it doesn't matter to me, it breaks up the process a bit too! Prices will go in for the bigger remedials.

One thing I do know is it's getting a full and thorough inspection before any dotted lines get signed

 

[timbobelfast]

Surely they must have a shut down scheduled in the year for essential maintenance? This sounds like a bag of nails. Good luck lol