Omega Owners Forum

Chat Area => General Discussion Area => Topic started by: Debs. on 18 March 2009, 19:45:05

Title: Calling OOF`s electrical experts?
Post by: Debs. on 18 March 2009, 19:45:05
I`ve been given a humungus air-cooled arc-welder, an old Quasi-Arc with range from 20-300 amps (at 60/90 OCV)......so, it`ll be very-hungry for current on thick plate welding jobs.
To slake the welder`s lust for power: I`m installing a 15 metre long, dedicated 6mm T & E radial, from a 32 amp. MCB in my barn`s distribution board to a 32 amp. 2P&E 'blue socket' for the welder in the workshop.

Question: Because the 6mm T & E cable has a smaller (2.5mm) CPC than the P & N; would it be advisable add a separate/additional 6mm. G/Y conduit-wire CPC from the 32 amp 'blue-socket`s' earthing pin back to the distribution board`s earth-rail?
*The incomer is a 'PME' earthed supply header.
Title: Re: Calling OOF`s electrical experts?
Post by: HolyCount on 18 March 2009, 20:04:03
eerrr .. pardon  ::) :-?
Title: Re: Calling OOF`s electrical experts?
Post by: Vamps on 18 March 2009, 20:06:04
Big wire, goes into big blue plug and to the fuse box......... :y :y :y
Title: Re: Calling OOF`s electrical experts?
Post by: Debs. on 18 March 2009, 20:06:25
Quote
eerrr .. pardon  ::) :-?

Granted! ;D
Title: Re: Calling OOF`s electrical experts?
Post by: RobG on 18 March 2009, 20:11:30
Quote
I`ve been given a humungus air-cooled arc-welder, an old Quasi-Arc with range from 20-300 amps (at 60/90 OCV)......so, it`ll be very-hungry for current on thick plate welding jobs.
To slake the welder`s lust for power: I`m installing a 15 metre long, dedicated 6mm T & E radial, from a 32 amp. MCB in my barn`s distribution board to a 32 amp. 2P&E 'blue socket' for the welder in the workshop.

Question: Because the 6mm T & E cable has a smaller (2.5mm) CPC than the P & N; would it be advisable add a separate/additional 6mm. G/Y conduit-wire CPC from the 32 amp 'blue-socket`s' earthing pin back to the distribution board`s earth-rail?
*The incomer is a 'PME' earthed supply header.
On that run I`d be inclined to use 10mm T/E and a 40A MCB
Title: Re: Calling OOF`s electrical experts?
Post by: Marks DTM Calib on 18 March 2009, 21:09:35
Yes, upgrade the earth as you are sudgesting!

I assume none of this install goes outside?
Title: Re: Calling OOF`s electrical experts?
Post by: Marks DTM Calib on 18 March 2009, 21:10:27
Quote
Quote
I`ve been given a humungus air-cooled arc-welder, an old Quasi-Arc with range from 20-300 amps (at 60/90 OCV)......so, it`ll be very-hungry for current on thick plate welding jobs.
To slake the welder`s lust for power: I`m installing a 15 metre long, dedicated 6mm T & E radial, from a 32 amp. MCB in my barn`s distribution board to a 32 amp. 2P&E 'blue socket' for the welder in the workshop.

Question: Because the 6mm T & E cable has a smaller (2.5mm) CPC than the P & N; would it be advisable add a separate/additional 6mm. G/Y conduit-wire CPC from the 32 amp 'blue-socket`s' earthing pin back to the distribution board`s earth-rail?
*The incomer is a 'PME' earthed supply header.
On that run I`d be inclined to use 10mm T/E and a 40A MCB

Although 10mm will give slightly less volt drop, there is no nead to increase the breaker size....unless you intend to start to draw 40A!
Title: Re: Calling OOF`s electrical experts?
Post by: TheBoy on 18 March 2009, 21:11:51
If you need help with the current regs Debs, let me know, and I'll give you my little bro's number, who is a sparky (dad was a sparky, so we're all pretty good)
Title: Re: Calling OOF`s electrical experts?
Post by: Welung666 on 18 March 2009, 21:13:44
Just run a half unwould extension lead from the house and make sure it's in a multi-plug with lots of other power hungry appliances :y

Only kidding :P
Title: Re: Calling OOF`s electrical experts?
Post by: Lioned on 18 March 2009, 22:42:33
Make sure you have an RCD at the origin,and do it in armoured if going anywhere its likely to get damaged.With pme connection you should have a good 'earth' return path so no need to increase the cpc.
Title: Re: Calling OOF`s electrical experts?
Post by: Lioned on 18 March 2009, 22:46:45
Also maybe best to get 'type C'  mcb if start up current high.
Title: Re: Calling OOF`s electrical experts?
Post by: Debs. on 19 March 2009, 10:09:13
Thanks for the advice and views everyone. :y

I`m going to stick with the 6mm. T&E (as I already have a reel of 'old-colours') ::) and add the larger additional CPC (earth).
I`ll supply the radial from the barn`s RCD, via a 32 A. MCB; there is a significant inductive-spike when initially switching the welder on, so it`ll be a curve 'C' MCB, but in use the current-draw would be within specs for the cable length and breaker (bearing in mind the 'non-continuous' planned use of high currents).
Non of the installation will be 'outdoors' and the barn is constructed of stone (i.e: not metal framed/clad).

My Father was an electrical engineer (HV power transmission) for 40+ years: so I was brought up around 'electrickery' ;).....but since his days; there have been so many changes to practice/regulations.

Thanks again. :y
Title: Re: Calling OOF`s electrical experts?
Post by: Marks DTM Calib on 19 March 2009, 11:39:06
Quote
Thanks for the advice and views everyone. :y

I`m going to stick with the 6mm. T&E (as I already have a reel of 'old-colours') ::) and add the larger additional CPC (earth).
I`ll supply the radial from the barn`s RCD, via a 32 A. MCB; there is a significant inductive-spike when initially switching the welder on, so it`ll be a curve 'C' MCB, but in use the current-draw would be within specs for the cable length and breaker (bearing in mind the 'non-continuous' planned use of high currents).
Non of the installation will be 'outdoors' and the barn is constructed of stone (i.e: not metal framed/clad).

My Father was an electrical engineer (HV power transmission) for 40+ years: so I was brought up around 'electrickery' ;).....but since his days; there have been so many changes to practice/regulations.

Thanks again. :y

The same field I worked in for Alsthom in Stafford!

Although we played with DC transmission setups at upto 400KV!

I suspect the in-rush spike wont be to big an issue, the C curve breakers are only really required for the likes of large induction motors connected close the breaker. Your setup will have a good run of cable with some resistance in it which will effectively lower the Q of the welders inductance from a breakers perspective and result in a flattening of the input spike.