To Mem or not ?

[needasparks]

Hi guys, Am doing a industrial job that will be using 32Amp three phase welders, there is not a masive budget on this job but common sense tells me to use Mem excel isolators due to the breaking currents but do you think I could get away with rotaries instead to keep the cost down or are they all cheaply made and a no go for this type of equipment.
Reason i ask is all will be on 3p&E sockets anyway, job has quite a few supplies i'm running and wanted to keep it uniform but the cost is knocking it up higher than i wanted. was just after your thoughts. cheers.

 

[malcolmsanford]

32 amp 3 phase switch disconnector merlin gerin metal industrial tp&n mgfl0323c - A1 Electrics

I have never used these but they are Merin Gerin so must be pretty decent quality I would expect, and a lot cheaper than MEM.

For welders as sure as eggs are eggs the welder is going to throw the isolator while the unit is still on and I would rather have the switching mechanism of a tine isolator than a rotary one

 

[mechelec]

Bearing in mind when the switch is opened it will see a back EMF from the welder the switch needs be suitably rated for breaking inductive loads ie AC 3

 

[Knobhead]

I’d go with Malcolm on this one. I’ve had to replace many rotary switches feeding welders.

 

[netblindpaul]

Remember that you also have to comply with PUWER98, thus the point of electrical isolation must comply with this reg also.
Remember PUWER is Statute Law.

 

[needasparks]

Cheers for your input guys, all much as i thought just needed a prod.
Thanks Paul I was aware of PUWER but TBH I thought it was general H&S stuff but not read it all as got bored when i had it mentioned some time back, from your comment I best read it through in case points are relevant to this.

I have not done many welders in the past, perhaps a couple of small ones years ago from memory so thought better gen up a bit, One I remember was two phase, which I understand is quite common. These are three phase and balanced as far as I know and running off the same sub-board so any tips I should take heed of would be good. If not pre-wired I was looking at SY as on plug, can you see any issues with that. cheers.

Edit
Did not say whoops, will be three or four on same DB.