three phase energy saving moudules pumps etc

[maddfridge]

hi everyone

we have a three phase supply (63 amp hrc fuses) which feeds a star delta motor control panel with interlocking door panel switch contactor. This is operated via a bms (building management system) , boiler control system and the energy saving system is wired in after the delta contactor output but before the motor windings.


I had the misfortune to have to disconnect three of these wonderful devices which had burnt out on some rather large pump windings at one of her majestys sites in the home counties.

The main water pump is fed on 16mm copper conductors per phase and had melted the motor windings and the red phase had burnt out the isolator caused two phasing of the motor windings and overload due to a mechanical siezure. The contactor motor overload burnt out and had welded inside allowing current to arc across the contacts in the main switch/ contactor

This fault was traced to a inline connector wrapped in just insulation tape installed recently by a major enegry saving company all names to remain anonimous to protect the not so innocent.

The 40 to 60 amps on a 16mm single copper cable wrapped in insulation tape failed badly in the metal enclosure rapidly causing a short to earth within the metal enclosure. This was all very avoidable as it would not have taken alot to put in a proper connection block within the enclosure.

Anyway i have seen these units on fridge, catering equipment and on lift motor etc

My logic questions how these inline connections without a manufactured covering of insulation fall within the scope of the 17th edition.?

thank you all for your very valued opinions

cheers tony was really tired when i posted this i did not realise it went on sorry chap
hope this clears things up.

 

[Knobhead]

I’d start again with your question, I haven’t a clue what you’re asking

 

[maddfridge]

I’d start again with your question, I haven’t a clue what you’re asking

cheers tony

The cable fault finding was only part of the fun as it burnt out the bms interface tyco jelnet as well
just for good measure
We had that pleasure this morning repairing and replacing a good few relays and contactor boards
Man with laptop due on monday morning leave that stuff to controls people

So really what i am asking is where does inline crimping fit in the realms of bs7671 surely that cannot have been a safe approved method of connection with insulating tape around it. i would understand if it was shrinkwrapped double layer like a Raychem kit or similar potted ?

i know you can get joint kits for single 6mm cables such stuff used on airfields and underground lighting stuff

cheers
maddfridge