Powering a MIG & compressor

[PandaWill]

Hi all,

Newbie to this excellent forum - looking for a bit of advice please..

We have recently moved into a house with a big garage (why we moved here lol) and I had intentions of equipping it as a workshop.

Now that time has come and I have my eye on a meaty compressor, and I intend to treat myself to a new Portamig 215 kit from Weldequip.

However bad news in that the sparky that came round yesterday said no way - I only have 2.5mm single wire old set up into the garage only designed for lighting and sockets.

To my knowledge both compressor and welder would both be single phase BUT 25/30 amp.

Can somebody please advise me on best way of powering this type of set up - would a generator be a good idea? If so what would be a good one?

Thanks all !

Will

 

[Robotstar5]

Welcome to the forum, a generator to power that lot would be into 4 figures so it would be cheaper to get your sparky to put a decent feed into the garage.

 

[brightspark]

whats stopping u running a heavier lead over to the garage

 

[Ed.]

Cheaper and better to run heavier cable, it's a one off cost and simple to do. Once done you can forget about it and you will have no more dramas. The cost of the cable and circuit breakers will probably be cheaper than what the sparky will charge for labour but it will still be significantly cheaper than a generator of that size.

 

[PandaWill]

Thanks very much for the info all.

The sparky implied it was a major job putting in a new 6mm cable.

Maybe I will get a second opinion from a different spark.

Many thanks

 

[the snooper]

if its a 3hp compressor it will run off a 13 amp socket
and the welder will run upto a certain amperage without blowing a fuse

but not both together

 

[brightspark]

Thanks very much for the info all.

The sparky implied it was a major job putting in a new 6mm cable.

Maybe I will get a second opinion from a different spark.

Many thanks

he couldnt be ar .,/././ed to do it more than likely

 

[PandaWill]

Agreed - I don't think he was interested in doing the work. I've got another spark coming round Monday next week.

The compressor is an oldish twin motor thing which requires min 30 amps.

Thanks all

 

[madkayaker]

I would expect the cable would be bigger than 6mm. You need to check that your spark is part P registered for this job. You might struggle to find someone that is sure what is needed as the average domestic spark will be out of there depth

 

[Ragnarok]

6mm is a bit small isn't it? for a workshop supply, mine is 16mm as far as i remember, with it's own consumer unit.

 

[Ed.]

6mm is a bit small isn't it? for a workshop supply, mine is 16mm as far as i remember, with it's own consumer unit.

I am not a sparky so take this for what it's worth...I think it would depend how far the run is from the main power inlet to where the workshop sub board is. Off the top of my head, at 240V, I think 6mm is good up to 40amps , 10mm is 60amps and 16mm is 80amps unless you are doing long runs say over 30mts.

The sparkies on this forum will correct me if I am wrong. But if you were actually running 60amps inside your shed, then probably you would have to also upgrade your main lines from the house to the power take off point as well, including upgrading the circuit breakers and RCD's

I ran 10mm to a sub board (about 6mts away) when I built my garage and then added another 16mm 3 phase circuit to another sub board inside the garage when I later decided to get a 3 phase MIG and lathe. From the garage sub board I ran 10mm to all the 3 phase switch sockets. The cable was the cheapest part of the installation.

Now I don't worry about whether or not I can run something.

 

[Ragnarok]

mine is about 30m probably and it comes off a huge fused switch that is taken off before the houses consumer unit, there is an RCD before it too though, never had it trip, but i don't think i've ever run 60amps on it, biggest MCB in the workshop consumer unit is 32amp and the main rcd is 45amp i think, neither trip with my mig at full power (sip topmig 195) or my arc but i don't think i've ever tried the full 300amps on that, i think the arcs max draw is about 45ish amps, never run full power though as i said, and usually i only have a few lights + 1 major machine in use at a time, and that setup has never caused me any trouble most of what i do is working on 3mm or thiner too so most of the time my welders are running at below half power.

i seem to remember that i worked out over 100m with armoured 16mm cable you could run 55amps, no expert though and i don't know about the upgrading "main lines from the house to the power take off point as well, including upgrading the circuit breakers and RCD's" everything here is pretty old and it's a farm so probably not quite the same as your average house anyway i don't have a huge draw on the power really, not most of the time anyway i'm sure that my arc on full power is close to the max that line could take, but that's fine, hardly use it anyway haha

 

[dannyp]

id use at least 10mm2

take a feed from the meter with it's own braker in a separate box trip then put a consumer unit in your workshop. id personaly use a split load one as well ( its not required ) but it means you can put the lights on a diffrent braker to everything else, so when you cut though the flex on on you angel grinder working late one night you only get a flash / bang rather than all the lights going out as well