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Electrical noise created by 3ph machine

Steve Phillips

Hello all

Life long sparky... semi-retired now, but working at a local workshop

The company had a local (rather shoddy) electrical company come in and re-supply a 3ph, 35A per phase painting/spray machine.    It was fed before and created flickering in the office fluorescent lights.

But, it still does it.  The fluorescent lights in the offices on the mezzanine nearby flicker when the machine pulls a high load.

It's fed from a sub DB that has a 125A, 25mm 3ph SWA supply (This run is considerable from the incomer - probably somewhere like 70M+.   

Machine MCB is 32A

They used 6mm 5 core SY cable (I would have gone 10mm) over a 25M run.  But they laid it on top of (not in) a 4" galv trunking with T&E inside.  Entirely possible the lighting feeds run within this trunking.

I may unstitch the cable and move it away from the trunking, but I am not entirely convinced that is the issue.

Any ideas on what to try?  

Personally, I would rewire the machine directly back to the incoming mains cupboard, but that is no easy task.

  • 0

    I have had a closer look at the lighting (I KNEW I would get roped into looking at the electrics here!)

    I am going to sort out the horror show that is the lighting.  Rewire it properly in conduit + plug-in roses and LED highbays.  Drop the circuits to 10A by adding two new circuits.

    Then the electrical company that just replaced the incoming DB and did a survey + certs (laughable), have agreed to then come and test it and sign it off.

    Thank you for everyone's advice

  • 0 in reply to mapj1

    Only 250W? Thats for girls!

    1000W GES tungsten lamps in vitreous enamel reflectors! Thats proper factory lighting.

    You didnt need heating either! Rows & Rows of 500W or 1000W fittings all beaming down their IR.

  • 0 in reply to Steve Phillips

    Signing off somebody else's installation work on an EIC is a bit iffy. IMHO, you should issue an EIC and if the customer wants more paperwork, the other sparks can do an EICR. Frankly, it's nonsense.

  • 0 in reply to AdrianWint

    Ha!

    Not my job but a colleagues, but over your self heating factory, I'll raise you a tale of metal parabolic reflector fittings on rusting jack chains that flickered when the hanger doors opened and they swayed in the wind.

    Closer inspection revealed a single rubber cotton covered snaking down between the chainlinks and into each lamp-holder . OK, that means the chains must be - surely not?  -ah well that is why they flicker then  ... as the rust slides and makes and breaks the return path.

    The past is sometimes a different world in terms of H and S, paperwork  and attitudes to  what is acceptable generally.

    But you are right, I've never had to change a 1000W lamp, except theatrical and that's not real wiring, or at least the real wiring rules do not apply - and I'm pretty sure that I've never needed more than a half inch socket set to do up a terminal either,  so maybe I'm just a low power softie really ;-)

    Mike

  • 0

    I did some investigating early this morning.  Basically, our company paid this sparky company to replace all the buildings DB's.  

    I checked circuits this morning and the DB listing is totally wrong.  Lights listed as sockets and socket as lights.

    I assume they changed it over and simply copied the DB listing from the old board without checking any of the circuits, or messed up the re-install (but I suspect a simple copy).

    Pretty shoddy.

    It's not a customer.... it's where I work

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