Cable calcs

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First time in industrial electrics so any help would be appreciated.
What voltage figure is used for cable calcs, 400 or 415. I am installing a welder on a 32a 3 phase socket. MCB is type c 32 amp, length of run is 30 metres. Owner assures me it is purely for the welder but I know engineers will plug in anything that fits so must go to 32 amp load. Cable will be surface mounted 5 core swa. If I have missed anything please let me know.

Many thanks
 
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I've used the tlc cable calculator, but cable can be 6mm with 415v entered or 10mm with 400v. You can see why I need to know what to use. It would be good to work it out by hand so I can refresh the old brain cell.
 
Allowable is 5% drop of voltage at incoming terminals. (Subject to manufacturers allowable for equipment)
 
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Just tried the Doncastor and it has used 415v. With the 32 amp socket rating comes at 4mm with a 9.6v volt drop. This feels too small for my liking. Will get the calculator out and have a go.
 
Are you sure that the Type C will cope with the welder inrush?
Using a type D will also need extra consideration with regard to disconnection time.
 
For the 17th edn regs use 400v.
4mm is a tad on the small side for my liking too, think it is rated about 33A flat out so any grouping or ambient probs and that is kicked into touch.
Looking at it from a Volt Drop pov, you are allowed up to 5% of 400v which is 20v.
Your length is 30m and the max current per phase is 32A.
6mm has a mV/A/m value of 6.4
0.0064 x 32 x 30 = 6.14v so 6mm is OK for volt drop.
Over to you to work out the efli for the MCB!
 
I've got an old BOC (350amp) which draws just over 60a on sparking up running on 10mm cable, and a MIG welder 300 amp which runs happilly flat out on 6mm cable with 32 amp plug and type c breaker
 
Calculations are on nominal voltage so 400 volt but for a welding set volt drop is not really that important. I will admit with the old BOC if the voltage gets too low the motors may fail but more likely to be volt drop in remote cable than feed to set.
Where the supply is only 32 amp I know they were a pain if someone forgot to wind the current down before switching off.
We used 3 of those old BOC sets to magnetise the rotor on the combined cycle generators on Connah’s Quay power station the new fangled machines had an automatic system to stop the rods from sticking so we could not connect them in series to get the 100 volts DC at 300 amp for 5 seconds we required to magnetise the rotor.
Not the main generator but a little I think about 40KVA stuck on the back which only job was to power the oil pump.
But most our new welders were inverters and could run on B type MCB. There are so many types of welding machines. First I worked on was Lincoln Bullet but electric drive and engine driven. The inverters were rated at 450 amp and input was over 32 I seem to remember 42 amp per phase off hand but they would run happy on B32 only when they were using air arc was there any problem.
But the old BOC’s we could put in parallel but not the inverter type which is why we needed bigger units with inverter type.
And we used 6mm SY on them all.
 
Doncastor
Where is Doncastor?

I live in Doncaster, which is a market town in South Yorkshire. They make cables nearby. ;)

Its a place up North that makes sugar. Anything North of Kings Lynn is Scotland as far as I'm concerned. :p
Sparks, thanks for confirming its 400v, now its out with the calculator to check earth loop. Thanks for all the help and spillchocker now switched on Steve.
 

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