contactor arrangement..

[steptoe]

I know Mr T, but if you dont understand it and simple follow our instructions it may end up just as bad,

you need to understand exactly why we are saying something so that you can work out if that does actually suit the situation you are in or not.

3 phase doesnt give many 2nd chances when it goes wrong.

there are even lots of meters out there that arent suitable for use on 3phase due to the voltage present.

 

[Sidewinder]

Steps,

Does that mean I should not have been clipping test gear onto the live lugs on the DNO side of the meter the other day on the 2x300mm sq tails direct from the 11kV sub on that 1.6kA per phase 3ph supply?... ]

 

[Mr T]

who said I dont understandi t , im not disagreeing with you , im simply advising you of how it is wired as opposed to how you think it should be wired...Live from MCB to Common on the switch , switched live returns back to A1 to energise the coil going NC to turn on the 3 phase board. Link from T1 (L1) on the supply side of the contactor to A2 bottom right of the contactor..415V on the load side of the contactor when switch is open

 

[kerching]

Steps,Does that mean I should not have been clipping test gear onto the live lugs on the DNO side of the meter the other day on the 2x300mm sq tails direct from the 11kV sub on that 1.6kA per phase 3ph supply?... ]

If you've got your Marigolds on and you are stood in a plastic washing up bowl, with one hand in your pocket then you shouldbe ok!

I sometimes get the 'pulsating sphincter' on the Merlin G 1600A panel boards!...those lugs are a bit 'snug'............... :coat

 

[kme]

I sometimes get the 'pulsating sphincter' on the Merlin G 1600A panel boards!...those lugs are a bit 'snug'............... :coat

Mate.....we had a pulsating Sidewinder; not just the sphincter :slap

And don`t mention being behind the PFC unit, with the covers off, when it switched a bank of capacitors in across the TP supply (and we don`t know how long since they last energised :run )

O/P -

So you`ve basically (if I read it right) got a "last man out" switch, that was originally supposed to isolate the TP board. Sounds like it originally had (or was designed for) a 230V supply for the coil, from the SP board, but either someone got the wrong contactor, or its been reworked since.

I`d personally like the contactor to be 4 pole - with a MAX of 230V switching (preferably lower). You`ve got a B6 protecting the phase coming from the SP board (would be good to know which phase that is), but nothing protecting the ?other? phase, being supplied to the switch through the contactor coil?

As was said:

Is the switch 400V rated?

Which phase is the SP board?

What is the load on the TP board?

What is the contactor rating?

Fusing???

Isolation to the incoming side of the contactor is what?

KME

 

[Mr T]

switch is a standard white plastic 230 V switch

SP board is either L2 or L3 will find out for definate Monday...

Load on the TP board is 2 no 3P lifts , a compressor , a couple of ring mains, a carwash 32amp, 3no 6amp MCB

not sure on rating there is a sticker on the side of the contactor but due to access I cant see the details..

isolation is to pull the NEDL 80 Amp main fuse either L2 or L3

 

[kme]

You`d have to pull all three to isolate the contactor itself, though - yes? So you need an iso in those tails ( TP or TPN as necessary)

So the 230V switch is supplied with 400V :red card

I stand by previous comment - it sounds like its been "modded" from the original design, to be honest.

One other thing is that the contactor enclosure would need to be marked as having TWO sets of supplies.One from the iso that doesn`t exist yet; and one from the SP board!

Your TP board has some SP loads on it - so there is a neutral requirement. ergo, the contactor should have a neutral accessible, which would allow single phase, 230V switching. Still needs a fuse, though!

 

[Andy™]

But as was pointed out, the 3 phase board is dead until the contactor energises, so L1 is at 0V

not if its connected to the feed side of the contactor

 

[ProDave]

not if its connected to the feed side of the contactor

Fuse protection?

With this setup, anything is possible.

 

[Andy™]

Fuse protection?With this setup, anything is possible.

only on the other live by the sounds of it