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Sparkyarc
I have just bought a used oil immersed arc welder, 30 - 180 amps. I understand from the seller that settings over 80 amps tend to blow the fuse in the 13 amp plug, so I intend to run off a connection from the electric cooker circuit, into the garage.

My question is, would I need to make a permanent connection to the welder, like a cooker, or is there a way to make a temporary connection with something more powerful than a 13 amp plug?

I trust that the cooker power supply will be adequate!?

Alan.
tighead
theres a good new invention out on the market sparky its called a ..........
30A circuit breaker

biggrin.gif biggrin.gif
simondrains
Sparkyarc, you can take a spur off your cooker supply - should be a 63A. You need to rate the cable properly, for current and length - use this - http://www.electricalsoftware.co.uk/produc...CFQJhMAod8BG3OA
- to calculate.

You should fit an RCD, to protect you, and ideally and MCB to protect the circuit. You can buy a "garage consumer unit" which you can refit with the right size components. And you should probably have it all fitted by a qualified sparky, but not if you don't tell anyone.

At the business end, fit a Blue C-form socket - probably a 32A, to suit the current draw of you welding set.

You can get everything you need from your local LX supplier. I could recommend some national chains, but I don't think i'm allowed on this site.

And if you sod it up and your house burns down, don't blame me!
frankieboy
when connecting welding machines via circuit breakers, you can use the "breaker trips".. there are several types on the market, the ones numbered from 1 to 4 and the others from A to D, .... say a D type 32 amp
The type 4 or D type are the ones that take a little longer to blow as when you turn on the mains, the sudden draw on the welder gives you an inrush current, and takes out the breaker... but by using a type 4 or a D type it is much less likely to happen, hope this helps..
all the best Frankie.
simondrains
Mate, ignore that link I posted earlier, it's tosh.
Try this instead
http://www.pandpelectrical.com/mpm/firevoltdrop.htm
But you need to decide what your acceptable volts drop is first. Normally 2.5% is reasonable, so 6 volts for a 240v supply.

Regards
Si
Sparkyarc
Frankieboy and Simondrains, many thanks for your advice, much appreciated!
Sparkyarc
Frankieboy, I have been strongly advised to do an "earth fault loop impedance test" before fitting a type d breaker.

Sounds impressive but has completely baffled me. Does this mean anything to you?
frankieboy
I think there are two types of ground / earth ... one is the return or as a lot of people call it the "earth" lead... fromo the clamp via a cable back to the the welder.. and you can also put a copper spike into the ground and attatch it to the bench via a piece of copper welding cable.. this has two effects, one is that should there be a bad welding return then any current will go back to the ground instead of going through ( shock ) you first, but some people have told me that you have to water these spikes to keep contact between the spike and the " dirt, soil " I think the impedence is a measurement of how good the conatact is, but a propper sparkie will assist you on that.. there is a member called "sparkie" on the forum who seems to know a bit, he may be able to help you if you can find him and message him direct, the copper spike into the ground also takes hf to ground to reduce the amount of hf emissions as well/.... all the best Frankie.
buzzboxboy
I have a very similar situation. I have just got a 110 amp oxford arc welder. I know I should give it a 15amp supply, but would it blow a 13amp fuse at 80-100 amps where I will mostly use it? Do those garage consumer units wire into your main house consumer unit? If you have a gap for another mcb on your house unit, could you use that for a supply to your welder? I know it's annoying to see someone asking so many questions but I'm hoping maybe I can do the job myself becuase I'm afraid of the cost of a professional installation. Are there any good books about wiring for total novices? I know this might not be the most interesting problem around but I hope someone can tell me something. Thanks,
Alex
LD50
Pretty sure the law was changed and unless you are a qualifed electrician you would be commiting an offence to modify you house electrics(replace sockets +light fittings is ok). you would be better off getting a qualified electrician to do the job and see if you can keep costs down by installing your own hardware and get them to do the wire up.
Tungsten sharpener
LD50 is spot on, I am a multi skilled maint tech and am qualified to work on and test any installation (just put in a 800amp supply for a new machine) but I cant fit a new circuit in my own house because I am not registered as part "P" compliant.

I live in the notts area and I would be happy to help you guys out by specifiying the gear needed and even doing the install but you would need to get a domestic spark to verify and test the work before going live.

As mentioned earlier, testing is required and this will include earth fault loop impedance which gives you the information needed to select the correct protective device.

It aint good to see people guessing at MCB ratings and suggesting how to select cables, I hear a lot on this site about guys sticking to their trade and this is definately one of those situations, a little knowledge can get you killed with this stuff.

E-mail me if you need any further info, but at least get a spark to design and test the install, so you know you are safe.

TS
pedrobedro
I trust that the cooker power supply will be adequate!?

As long as nobody decides to do any cooking till you've finished welding laugh.gif I wired my shed with its own 40amp supply from the house to a 4 way wylex box in the shed, old fashioned wired fuses as trips go off as soon as you arc up. This was years ago before regulations were tightened up but I have had no problems running a 170amp erfi mig on it with a 13amp fused plug.
Stupid Welder
Hi all,
The old machines use power all the time,got a saf 260 ac/dc that i dont use anymore cos it throws the circuit breakers when i turn it on,not every time but got jacked off going to switch them all the time.
New machines go onto a stand by mode,got a Lincoln 130 stick plastic thing,runs 220/240 volt,will handle a 3.25mm lo hyd hours at a time,and they're not expensive.It is an old odel,1 of the early ones.but it still does it.
Also got a Lincoln 350 C Pro 400v dont have any problem with this,saf also 400v.
Get rid of the energy sucking oil cooled thing,an solve your problems in 1 go.
Oxford bantam,or a copy of.

SW
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