Welder taking out MCB

[Knobhead]

For some reason this PC has found a new trick. Have now got the fonts sorted, it’s started doing double posts!

 

[ash_s3]

Thanks Tony, this welder is being used in an industrial unit for a metal fabrication business so needs to be fairly hefty for welding 10mm plate.SIP have emailed me confirming it needs a 40a supply and the chap was unsure why it had a 16a plug attached! He Said the 2.5mm flex was ok as it only draws 40a for a small amount of time then settles to around 30a!!

 

[Knobhead]

The cable size still needs looking at, it’s too small.
Still your mate could wrap the flex around his mug to keep his tea warm.

 

[davelerave]

you would stand a better chance with the 20amp 3-phase model if it could be swapped at all


you may even get away with the existing 2.5 final circuit assuming it utilises only 2-phases

which i think is the case


why is a 40amp SP welder supplied with a 16amp plug and 2.5 lead? nothing surprises me with new equipment lately

 

[ash_s3]

Welder cant be swapped as its about 10 years old!

Can you get larger flex than 2.5mm sq?

 

[davelerave]

so it's an old model -wonder if it came pre-wired at all?


looks like the lead+plug and final circuit are undersized then

also you'd need to check the suitability of supply and sub-main for SP welder


i would prob try welder at sub-board

as you might still be underpowered even with new final circuit


it'll be simpler if all existing loads are SP rather than 3P

 

[SPARTYKUS]

Along time ago I tried using my SP SIP 105 mig to weld a friends narrowboat. On the canal bank, on an extension lead about 50 M from the plug (on the canal side).

As you can imagine, it was like as much use as platting fog

 

[ash_s3]

Dave, there is no sub board. Its a small unit on an industrial estate, 3Phase supply - TNCS going straight into 3 phase Schneider DB.

SiP said the welder uses 30A constantly on max power, but can draw a peak 40A for a very small amount of time on initial start-up, would a type C/D curve 32A MCB allow for this, that way i can use a 4/6mm SWA and use 32A socket and plug without exceeding the rating of them.

What a pain in the arse this job has turned into! Started with... "can you just wire a 16A socket in for me"

 

[davelerave]

ok sorry i though it was a shed or something

i'd prob test it at board on D type mcb, see if it's working properly and then size final circuit if all goes well

volt drop shouldn't be an issue on IND unit if there's spare capacity on a phase

 

[davelerave]

Along time ago I tried using my SP SIP 105 mig to weld a friends narrowboat. On the canal bank, on an extension lead about 50 M from the plug (on the canal side).

As you can imagine, it was like as much use as platting fog

i'm hoping to learn how to weld soon:yesnod:-never got round to it

 

[SPARTYKUS]

It's bl00dy brilliant fun.

Although the welds can hurt as you look at the drip metal on your arm, and then 3 seconds later realise its working its way through your arm like chernobyl is working its way through the earth on its way to china

 

[ash_s3]

ok sorry i though it was a shed or something

i'd prob test it at board on D type mcb, see if it's working properly and then size final circuit if all goes well

volt drop shouldn't be an issue on IND unit if there's spare capacity on a phase

How do you mean 'test it at the board on a D type MCB'? Wire the welder flex into the DB on the 32A MCB and check it doesnt trip?
Can you get 4mm flex?

The board is literally empty, 1x Ring main, 1x Water heater, 1x Lighting circuit

 

[Granty666]

I’m about to buy a Stahlwerk CTM-250ST.
I contacted them about a note on website regarding residential use and electromagnetic interference. Their clarification was with regard to public low power supplies and danger for people with pacemakers. I also asked about electrical supply suggesting 32A/40A Type C MCB ON 220/240 circuit. Their response was: “ I need a 16A socket outlet and 16A Type C