xlpe cable

[johnmf]

got a 130 amp 3 phase welding machine to power up.

the supply is from a bussbar adjacent to where the machine will be. i intend to use swa cable from a tap off box on the bussbar. the cable is 4 core 16mm (got some left over) which i intend to protect using bs88 63A fuses in the tap off. does this set up sound ok?

the cable is xlpe type though, bs 5467 i think it is. will this make a difference than if i used normal 70 degrees swa type?

also been looking round for a suitable switch disconnector to connect the cable/set to. it seems that all good brands jump from 100A straight to 160A. (not cheap either,£300+). anybody got any other suggestions or places they recommend i try obtaining a switch disconnector from or suitable alternative's?

cheers

 

[Belle427]

rs components carry 63a switch fuses for about £130

 

[johnmf]

cheers for that

but i require one at least 130 amp seen as thats what the welding set pulls

 

[JohnD]

cheers for that

but i require one at least 130 amp seen as thats what the welding set pulls

Does that mean 130A per phase, or 43A per phase?

In electrician-speak, 63A means either 63A single phase, or 3-phases at 63A each.

 

[johnmf]

its 130 A total so yeah 43 amp per phase.

 

[JohnD]

Then a 3-phase device of 43A or greater is what you need. There is a surge calculation for welding gear which I don't know. I believe they usually take "D" type MCBs.

 

[Belle427]

just checking but is 130a the welding current?

 

[Lectrician]

I wouldn't use XLPE on a busbar arrangement - pointless. Unless it's left over.


A welder that takes 130 amp per phase would vaporise what ever it was welding 50amp a phase sounds more like it - get a 63amp rotary isolator, back this up by a D type 63amp breaker (or even a 50), calc the cable size based on the EFL and Vdrop.


When you say busbar, are you talking about a small meter long busbar, or a factory wide one??

 

[Belle427]

not sure on the regs but isnt rcd protection also a requirement?

 

[johnmf]

its 130 amp total so i presume thats 43 amp per phase if balanced.
its a factory wide bussbar.

you say 63 amp isolator, when they are rated does the rating on the front refer to the amps per phase? (i.e, ive got a spare square d isolator, this has 100A written on the front. does this mean it can take 300 amps?, i.e 100 per phase?)

if so its ok to use yeah?

also the protection has to be fuses because of the tap off box. the box takes bs88 industrial type links. what rating do you recommend in each phase?

 

[johnmf]

not welding current no, the set says on the back and in the manual, maximum current requirment I1=130A

 

[RF Lighting]

A welder that takes 130 amp per phase would vaporise what ever it was welding

I did a 100A per phase welder years ago.

It was used for welding the buckets for the front of quarry wagons.

The buckets were so big the last weld had to be done in the carpark, as they wouldn't fit out of the factory doors

 

[Spark123]

back this up by a D type 63amp breaker (or even a 50), calc the cable size based on the EFL and Vdrop.

I'm just thinking how low of a value of efli you would need for a 63A or a 50A type D breaker, just thinking would he be better off going for fuses?

 

[Lectrician]

He will have to go for fuses - It's factory busbar-trunking with plug-in tap offs by the sound of it.

Appliances never usually spec the total current draw by adding the 3 phases together - odd.

All switches etc are rated per pole. A 100amp double pole is 100amp per pole, a 100amp triple pole or four pole is 100amp per pole.

 

[JohnD]

...Appliances never usually spec the total current draw by adding the 3 phases together - odd...

I bet it's a trick to make your welder sound more powerful than it really is. Like cheap stereos - "Only 5watts per channel? Lets add them together and make it seem like more"