peak4 | 12/01/2020 19:21:48 |
![]() 1322 forum posts 147 photos | A general query about welders/transformers and MCBs in the workshop. I later picked up an older oil cooled stick welder, with the intention of running that off another dedicated 16Amp socket. The (different) seller ran it off an MCB, rather than a fuse, again I believe a D16, but said that he just needed to power it up initially at one end of the current adjustment, and then after the transformer had saturated, he could weld at all of the available ranges without a problem. He ran it in his other workshop via a fused outlet. The 16Amp sockets are each fed with 2.5mm² twin and earth, radially to dedicated MCBs, so the cable should be good for 20A Cheers Bill |
JohnF | 12/01/2020 19:56:32 |
![]() 1034 forum posts 148 photos | Hi Bill, Electricity is not my forte other than simple ring main and lighting wiring etc, however I had the same problem with my welders. The MIG ran just fine but my TIG which also has a stick welder outlet was a different story, for many years I had only a fused supply but we had the house upgraded to a modern RCD / MCB unit and I also did the workshop with a dedicated circuit for welders only as well as the ring main and lights. From that point the TIG welder would start OK but after a singe run it would trip the MCB thereafter when trying to start a weld so contacted our spark who came and changed the MCB to a different rating - problem cured. Trust this may be helpful but I am not competent to offer definitive advice but I can if you wish look at the MCB rating he fitted please let me know. John |
Ian McVickers | 12/01/2020 19:59:47 |
195 forum posts 91 photos | Try a D20. This will supply a higher inrush current. |
peak4 | 12/01/2020 20:20:23 |
![]() 1322 forum posts 147 photos | Posted by Ian McVickers on 12/01/2020 19:59:47:
Try a D20. This will supply a higher inrush current. Unfortunately, I don't think it's quite that simple. Hence my problem, that a D20 at the workshop end will trip at about the same current as the C40 at the house end. Bill |
Dave Halford | 12/01/2020 20:26:29 |
1142 forum posts 11 photos | Bill, It's possible your 16A D type is a bit quick off the mark if it's a budget brand. Get a Schneider A 20A type D will give you the discrimination you need with the house, I wouldn't drop to a C you still need the high inrush protection the C can't supply. Don't forget a D is just slower to operate so the inrush is in effect ignored the figures you are worried about are instantaneous values Edited By Dave Halford on 12/01/2020 20:31:44 Edited By Dave Halford on 12/01/2020 20:43:44 |
Neil Wyatt | 12/01/2020 20:29:56 |
![]() Moderator 18409 forum posts 718 photos 78 articles | Best suggestion I was given is - use an extension lead. Neil |
peak4 | 12/01/2020 21:31:03 |
![]() 1322 forum posts 147 photos | Dave, I'll double check, but I think the D16 is a Schneider Neil, I did think about that whilst I was typing up my original query. Why I never considered it before, I'll never know. Anything will have to wait a day or two though as I'm otherwise engaged tomorrow. Bill
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Emgee | 12/01/2020 21:35:27 |
1825 forum posts 240 photos | Hi Bill I would advise to remove the existing garage supply from the consumer unit and fit a SP&N Switch fuse with a 63A BS88 fuse for protection supplied direct from the incoming supply tails. Then as suggested uprate the mcb supply to the welder to a D type. Emgee |
Steviegtr | 12/01/2020 21:58:43 |
![]() 1778 forum posts 235 photos | We always used D type circuit breakers for welders in industry. Or the earlier ones were HRC fuses. Now out of date really. Cannot remember because of my old age, but the trip capacity of a D type breaker was very high. Always used C type for Ring mains & A or B for lighting. On control panels we used a device called a MMS or manual motor starter. These had auxiliary contacts for other uses. |
Mark Rand | 12/01/2020 22:40:30 |
946 forum posts 8 photos | If it's an Oxford/Pickhil etc. Bantam or equivalent welder, it really needs a D32 to supply it. Cost me a few breakers to work that out. If you don't want to automate anything, wire up a box with either a 15Ohm 100W resistor or a kettle element and a switch to short it out, in series with the mains lead plug the welder in with the switch open, then short the resistor out before starting to weld. That'll limit the inrush current to no more than 16Amps.
I recently sorted the same problem on my electronic multi process welder that has replaced the oil cooled one. That had the problem that the inrush current to its power supply regularly welded its switch contacts closed
PS, anyone need an oil cooled welder? |
Steviegtr | 12/01/2020 22:53:39 |
![]() 1778 forum posts 235 photos | Don't forget with the bantam & any oil cooled welder to at some point change the oil. It's dialectric strength breaks down & they end up taking more current than needed. |
Steviegtr | 12/01/2020 22:54:42 |
![]() 1778 forum posts 235 photos | To add you can usually tell when the oil needs changing by the smell of the oil. Hard to explain. |
larry phelan 1 | 13/01/2020 14:19:58 |
903 forum posts 17 photos | Not sure if this will help, but when I installed my Transwave rotary converter, I was advised to make sure I fitted trips suitable for motor running [I think they are type "D" ] It seems the D type can cope better with the surge when the motor starts. Anyone out there know more about this ? I bet there is !!! |
Howard Lewis | 13/01/2020 16:18:33 |
4136 forum posts 3 photos | Possibly, you need a MCB with a longer reaction time, equivalent to a slow blow as opposed to a quick blow one, Not being an electrician, this is probably the difference between the A, B, C and D types. Howard |
Steviegtr | 13/01/2020 16:30:42 |
![]() 1778 forum posts 235 photos | Yes it is. Simply starting with the ( A ) type mcb for light standard type resistive none surge loads. Lighting etc. If a lot of fluorescent lighting then up to ( B) . (C) Nearly always for Sockets & ring mains etc. The (D) type for motor circuits or anything with a large surge. Sorry cannot remember the KVA ratings of them any more. Hope this helps. Retired Electrical contractor. Steve. |
Nicholas Farr | 13/01/2020 16:59:43 |
![]() 2549 forum posts 1210 photos | Hi bill, is there a ratings plate on your welder? It is quite possible that you will need a 32amp supply for an oil cooled welder, even if you can get it powered up. It won't mean that it'll draw 32amps all the time that you are using it, but it may need the extra power for striking the arc up. Regards Nick. |
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