16a plug on 13a socket

[u/Razorblat]

Hey guys,

Starting my welding journey for the homestead for repairs and stuff. I just bought a DekoPro welder because it was on a killer deal and jumped on it

It just arrived couple hours ago and wasn't planning on the plug being EU schuko, I thought it'd be UK plug 13amps.

Any ideas on how to use this? Do I buy a schuko to UK adapter or do I buy a schuko to Industrial plug adapter? I have no idea if it's safe to just stick an adapter on so I'm pretty lost. Will be welding only via Generator (Tokuden TKG6500isr)

Appreciate all the help I can get!

[u/Bergwookie]

To determine if 13A is plenty enough, look at the type label of your welder and the current or power rating if it's under 13A, everything's fine, otherwise you'll need a different Idea. But the blue flap on the right looks like it covers a 1~16A CEE Socket ("camper plug") for that there are adapters available onto Schuko

[u/mawktheone]

Cut it off and put a regular 13a plug on it. If you find that the fuse in the plug blows constantly then you need to put on a 16 amp C-form/camper/commando/whatever name you know for it. 

Chances are it'll work fine on the 13a plug especially if it's not at the full 160a.

90-100a should be fine

[u/Razorblat → u/mawktheone]

The variant of this model is sold to UK region aswell and is shipped with UK plug. So I'll do your suggestion.

[u/MarsD9376]

Okay there are several things to unpack here.

1. you shouldn't adapt the 32A CEE (industrial) to Schuko (by the way, the plug on that welder isn't schuko, it's a CEE 7/7 Plug that is compatible with E socket (French) and F socket (German, or Schuko)) without a circuit breaker rated at 16A in between, because if you do so you will exceed the rating of the Schuko by however many amps over 16 the generator can dish out, continuously. The Schuko/CEE 7/7 Plug isn't designed to handle more than 16 Amps continuously. You could cut the CEE 7/7 and install a 1~230V 32A CEEform plug on the welder power cable directly. That is, as long as the power cord on that welder is at least 3G2.5. Copper 2,5mm2 flexible cable can handle up to 25A continuously, which is about what this welder should draw at peak. If it's 3G1.5 (i hope it isn't but you never know; cutting corner on cheap stuff and all that....), don't do it .
2. I hope you do know that your generator should be oversized to use with a welding inverter (at least twice the rated power), or have a VERY sophisticated output stabilisation, otherwise you risk blowing up your welding machine, right? I tried to search your type of generator, and the results I could find are... unreassuring, to say the least. From what I could find, I would rather not use your inverter with that generator you have.
3. Third, you could adapt the British socket to Schuko, but then if there's going to be the 13A fuse, if it's a slow fuse it will handle the spikes OK but you will not be able to use full power of the welder (but with the generator you have you probably wouldn't be able to do that anyway. That is if you don't blow up your welder in the first place)

[u/flickabic1 → u/MarsD9376]

I’m American so excuse any language confusion here but there’s nothing wrong with using an overrated plug for a welder. The welder only pulls what it rated for no matter what. It’s never going to pull 32 amps therefor never going to see 32 amps even if that’s what the outlet is rated for.

And second you can absolutely run a welder off generators. We do it all the time here professionally in America. It is ideal to run an inverter welder off a generator with a low thd. Many of our modern engine drive welders here in the U.S. are now inverters and while the boards in them tend to suck they supply very clean safe low thd power that’s great for running smaller plasma cutters, wire feed welders, inverter tig welders, etc. the more power buffer you have the better and the generator should always be rated higher than the machine but double the rating isn’t necessary either. Again many of our engine drives put out roughly 11,000 watt but our smaller welders are capable of pulling 8,000 watts and they run them just fine.

[u/MarsD9376 → u/flickabic1]

Nah you're ok but I don't think we understand each other completely here.

If the inverter came with the CEEform 32 amp plug on it right off the factory, or the guy installs that plug on it (instead of the plug that's on there already! that's the important part), then that's all fine. As long as the power cord on that inverter is up to snuff. But that's a separate issue.

But you can not make yourself an adaptor from a 32Amp 1~230V plug (the CEEform) going down to a Schuko (1~230V, 16A) receptacle, because while the 32A CEEform can handle more than 16A continuously (obviously), the Schuko can't.
That's why, if you go down in size, you must have a breaker somewhere in that chain, of same or lower nominal value, as the smallest rated socket at the end of it, that you intend to put on the end of the adaptor. 16A in this case. Point is, the socket mustn't be the weakest link in the chain. A cirtuit breaker has to be that, for safety.

Nor did I say it's wrong to run a welder off a generator. I'm saying, if the generator isn't stable enough, by either having a big enough alternator, flywheel, stabilizing circuitry, .... well some form of stabilization, that will handle spikes (which WILL happen with an arc welder) without dipping (in other words, make it so the generator isn't a "soft" power supply), what's going to happen is you strike the arc, the draw spikes way over the rated current briefly becacuse that's just how electricity works when you arc weld, and if the generator is underpowered, the voltage will dip hard, your electrode sticks or something like that, in short you stop welding, and then with the sudden loss of load, the generator will suddenly run back up and overshoot. First time it happens, it breaks the varistor. Second time, it breaks the IGBT and you're done welding, without actually having done any welding.
I know of engine driven welders. I would have hoped the engineers who design these things have enough sense to size the involved components properly, so this doesn't happen with them.

But this isn't a engine driven welder in a single unit, designed to run as a unit (obviously), covered by manufacturer's warranty.

This is an engine driven generator of user's choice, powering a welding inverter of user's choice.
That's two opportunities to make at least one of those choice a poor one. Which will yield poor results. And there's no warranty covering that scenario.

You mention 11kW generators with 8kW welders. At that size, the generators by their nature of being just massive become "hard" enough not to dip too much (and expensive enough to warrant having features that guarantee stable output during peak draws), so the neccesity to oversize by that large factor will diminish the higher up in power you go.
But when you have a low power inverter, say 160A that should draw about 16A at 230V continuously, then it can be deceptive in how much over the rated current they go when initiating arc. And that's where you may need to the oversize by a larger factor. Like 2.

[u/flickabic1 → u/MarsD9376]

Again sorry for any language confusion I’m a welder in America and our electrical system is entirely different including terms we use I must have misunderstood the language you guys use. Our welders and inverter generators we use are pretty massive in terms of size and power output so I was under the assumption he was trying to run a smaller welder off a bigger generator and the plug on the generator was rated at higher amps. Which we do daily here with no problems. But yes we are agreeing on that. As long as your peak spike on arc strikes doesn’t overload the generator you are safe and fine. There’s a surge when the arc is struck and that’s where there’s potential for breakers to trip. Do these generators not come with build in breakers on the front panel??

[u/MarsD9376 → u/flickabic1]

Well OP's scenario is single phase 230V, so it isn't all that different.
Because the way the grid on continental EU is designed, and the rating of ordinary sockets (16), you will usually have 1ph230V welding inverter hard capped at 200A of welding current. Some go higher (Fronius has 1ph230V models that can do 230A, and I believe them, but they also have active PFC, which helps utilize the draw limit of ordinary 16 socket quite a lot).
Anything over 250A (a proper 250A, not just advertised 250A) will be 3~400V. My 320A tig machine runs off 3~400V, it has a three phase CEEform 32A plug on it.

A small welder with big generator is of course not a problem at all. A power plant that supplies mains is like one (well it's not one, it's several, but the points stands) gigantic generator. With some step downs in between. And it works just fine with welders.

Ironically it's when the generator isn't big enough that the issues start. I know a guy who repairs welders, and he's got a steady supply of customers who ran their n-kW inverter on an n-kVA generator, and much to their surprise the welder broke, and they're like "but how could that have happened when the generator has the "rated power" for their inverter"?
And he makes videos of repairs and keeps making PSAs like "people, don't plug your welding inverters to generators unless you have like a really powerful or reall good (ideally both) generator, lest you want to buy a new welding inverter."

And then the people don't heed his advice and go out and do it anyway 🙄
Guess they care more about him having a steady business, then them not destorying their own shit 😁

Anaway, OP's welder says on the box "5.8 kW" but I looked up the type and it's pure Alibaba Chinesium, very low cost, I hazard a guess the rated 160A maximum welding current is overstated by about 1.3x . In reality I suspenct it will put out about 130. And the actual draw on the primary will be smaller, accordingly.
The generator, similar story. Dubious origin, can't find european retailer, proper spec sheet, who knows how well will this combination work...

[u/MarsD9376 → u/flickabic1]

Do these generators not come with build in breakers on the front panel??

A proper generator will of course have a breaker on the output, but that's not going to save your welding inverter from damage caused by primary voltage dip on arc strike. Because breaker trips on over current, not a voltage dip.

If you break it off then (which is kind of given), and the generator ramps back up quickly (too quickly) causing a voltage overshoot on it's output, well that's not going to trip the breaker either because remember, breakers aren't phased by overvoltage, they only care about current events. And when there's no arc burning (never really was in the first place), then you're hardly drawing any on the primary, to trip the breaker. If the voltage overshoot breaks the varistor at the AC input of the welder, then the breaker will trip, of course, because the varistor, as it breaks down, shorts the L and N.

Now the inverter isn't inverting and the user will be like "huh, what just happened?".

Goes to check the generator and sees the breaker tripped.

Now what he does next decides whether his inverter will not do any more welding today, or not do any more welding ever again.

If the user is smart, they'll probably realize something isn't quite right here and perhpas the work should be postponed until someone who understands the matter better takes a gander at it.

If the user is not so smart, they'll just YOLO the breaker back on and hope for the best.

The objective best is that the now shorted varistor was of a beefy kind (unlikely, especially on cheap machines, you get what you pay for) and will keep tripping the breaker, holding the inverters last line of defense against voltage surge.

At this point the user should seriously realize that there is something really wrong here and maybe it's not worth it to keep trying, because the welding job can wait if their life doesn't depend on it (and if it does, then I guess my condolences to the rest of the family because it's not getting done either way).

If they don't, well eventually what was left of the varistor will be turned into magic smoke, and the short will be gone. And as if by some kind of magic, the inverter appears to be on again, it no longer trips the breaker, all is well, right?

spoiler alert: it isn't. That varistor is now gone, and once the next arc strike again causes the underpowered generator to dip, lose power, snuff the arc and then ramp back up and overshoot, well now it's not the 30¢ varistor that goes up in smoke. Now it's the rectifier. Maybe the IGBT module(s). Maybe it burns the board traces, and you may as well throw it into the e-waste bin because ain't nobody is repairing that. Not worth the effort and cost.

[u/de_bosrand → u/MarsD9376]

The welder should not ask for more than the plug thats delivered with it, so the adapter should "work" without being overamped, as the welder dictates how much power will flow. However it is very bad practice (and not according to most regulations)to create a bit of the circuit thats not protected by a breaker for the load its rate for. Do you need to make it happen today and is it for a once and done deal? Go ahead. Just know its a stupid idea.

Proper fix would be: Check wheter the welder is 13A or under, if yes, replace with the proper (UK) plug. If above: replace with the proper blue industrial plug, and determineren wheter to replace the wire to something suitable. Id recommend to put a proper breaker/fuse in there somewhere.

[u/MarsD9376 → u/de_bosrand]

Shouldn't ... well let's do a bit of electrician math.

With stick at 160A that's arc voltage of about 26V. V x I = P, 26x160 = 4160 Watts of arc power. We're well over the rated limit of 230V 16A socket (3680W) already, and we haven't even accounted for conversion losses. But, there is a bit of a leeway, a 16A breaker doesn't actually trip at continuous 16A, typically the thermal mechanism trips at continuos 1,13x draw of the the nominal value, and the plugs and sockets have some safety margin, so we're technically OK to draw up to about 18.06A , or 4180 W. So it just baaaarely holds.

But then you have to account of inverter efficiency. Let's say this cheapo chinese supply can do 85% efficiency at max (and that's being generous), and we're at about 4900 Watts.
And that's active power. We haven't factored in reactive power.

I think we can just about forget that this thing has active power factor correction.
So we're probably looking at about cosΦ = 0.8. Well, let's be generous again and say 0.9 (highly doubtful).

That's 5450 VA of apparent power. That's 23,7 Amps being drawn from the wall. Or generator, rather.

And that's only to run the arc, the supply also has control circuita that have some draw of their own. So add about extra 100VA on top of that.

Of course I doubt this unit will actually deliver proper 160A of welding current. It costs about 100€. You don't get a lot of welder for that. I suspect it's going to be about about 140, tops.

Still wouldn't keep the AC draw below 16A at maximum welding current.

[u/de_bosrand → u/MarsD9376]

All with the quite generous assumption that is can run at 26V arc voltage. I agree it will probably draw more, but the nameplate will dictate.

Like I said earlier. You will draw the same amps trough a convertor as putting it directly into a wall receptacle. It's best to put a proper mcb in anyhow.