Any Electricians?
Turbo Mini Forums

Been having problems with my Spot Welder. I do a couple of spots in quick repetition and the breaker trips. No trouble with the MIG.

I've had an email conversation with manufacturer (SIP) and he's pointed me at an under rated and worn (possible??) breaker. To quote him:

"current at which this operates is denoted by the letter prefixing the current rating.
B type trip at between three and five times the rated current and are generally reserved for domestic and very light commercial use.
C type trip between five and ten times the rated current and are used for everything from motors to fluorescent lighting.
D type trip between ten and twenty times the rated current and are used for very inductive loads such as very large motors and welding equipment. "

I have a B20 breaker for the garage, so I'm guessing I need that swapping for a D20.

Will I need to redo/ammend the part P cert if I have it changed (the whole house is certified to July 08 regs)?

Is it something I could/should do myself or better left to a pro - i don't like ellectricity. It's witch craft!

Ta

EDIT: Sory I spelt Electricians wrong...

Edited by apbellamy on 25th Sep, 2009.

Not a good Electrician myself. Perhaps the spot welder pulls too much of a surge. Where the MIG is more constant. A full 30 amps to the garage will sort it out? I have a B50 trip fitted.

Edited by Jason G on 25th Sep, 2009.

try uprating the breaker and see if that helps. Also what rating is the cable to the garage?

don't worry about the part P, it was like it when you moved in
.
If you are not confident with electricity, then leave it to the pro's! Seriously it could kill you! for the sake of £50 i wouldn't risk it

if its a straight swap, ie size for size (physical dimensions) then do it yourself. electricity only bites when you dont respect it!
Im a wire monkey/panel builder at work and check things several times. Especially on power up's with 3 phase!

104.7bhp NA
14.36 1/4 mile
5.3sec 0-60

Not sure what rating the cabel to the garage is, but I know it's armoured and about 1" thick. The sparky who did the house said it was about twice what I needed even for serious power use.

Unfortunatly I had a new consumer unit fitted when the part p was done....

Sounds like the best plan is a D50 breaker fitted by a pro.

Thanks for the advice

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A man without a project is like a like a woman without a shopping list.

Changing a breaker is a piss ball, just turn the main switch off and then you are working dead, and effectively just changing a fuse.

Thanks for the advice gent's.

I've passed the board and welder details onto an electrician friend of John's (minimadmo...). He's going to spec me the correct breaker and fit it for me. Job's a good un and hopefully my week of work to crack on with the mini's shell won't be wasted....

I had exactly the same at my last house with my SIP spot welder - it has a crappy transformer in it (to keep the size and weight down) and is highly inductive.

Mine used to trip a 32A RCD, at random (depending on which point the AC cycle was at when I pulled the trigger) but the consumer unit was in the garage so there was hardly any cable length (to add a bit of resistance in the circuit) which didn't help.

However, your main problem could well be the 20A.

If it's the same model as mine, the rating plate says 2KVA at 50% duty, 11KVA maximum welding power. The two figures do somewhat contradict themselves but if there is any truth in the second figure, it will be pulling a lot more than 20A on the primary side.

You can't just increase the current rating of the RCD unless the current rating of the cabling etc is adequate, and if so, they would have installed the next size up (usually 32A) anyway.

Try it somewhere else in the house on a circuit which has a 32A RCD and see if it still happens.

Schrödinger's cat - so which one am I ???

Thanks Rod

The welder is a P1PM (iirc).

230V, 12.5KVA and 7200AMPS Short Circuit Current (from the plate on the end).

The only other 32A breaker is for the cooker so I can't really try it anywhere else...

As said above, i think you may be over the 20A with that unit. Definitely worth swapping for a 30A supply if possible, and a C type breaker also.

Of course all of this relies on the cable csa being adequate.

Finally got this sorted. Spark has been round and put in a 20C rated breaker and Bob's your mother's brother. Spot welding is back on