220 Connection

Be careful. If I had 50 amp wire and 50 amp cable I'd up the breaker to

50 amps. In some cases, such as motors, you might even want to go to 60 amps because of the starting torque. In this case don't exceed 50 amps. It should be safe. Even if there is a short the breaker would still protect the wire.

If in doubt get an electrician to take a look at it for you.

Al

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snipped-for-privacy@shaw.ca wrote:

Moving the ground to the neutral will not fix anything because the neutral and ground are tied together at the panel so they are electrically connected. Even though they are electrically connected the grounds are to be connected to the ground busses and the neutrals to the neutral busses.

If the welder is not broken and is wired correctly, a possible cause is the breaker will not handle the starting surge. Breakers do get weak and changing to a new breaker may fix the problem. I that were the case then I would certainly get a 50A breaker if the circuit is all rated for that current. If you have an electric stove with a 40A breaker you could substitute it to see if it fixes the problem.

Billh

Hmm -- I wasn't sure if the OP was saying that he had 50 amp wire (#6?) running from the breaker to the outlet, or whether he was saying that he had

50 amp wire and plug running from the welder to a 30 amp outlet. By all means, if the wire from the breaker box to the outlet (or from the breaker box to the welder if you've wired it directly in) is heavy enough to support higher amps, go ahead and put in a larger breaker. On the other hand, if the wiring is not sized for more than 30 amps, I'm not sure I'd want to go that route. I've read several times on this newsgroup that you can use a smaller wire for a welding outlet than you can for other applications, because of the intermittent nature of welding ... but I don't know how far you can push that, either legally or safely!

Here's another thought: Do a google search on "power factor correction" on this newsgroup. We had an extended discussion about this a couple of months or so ago. It seems that transformer-based welders circulate a good bit of current through the breaker even when idling. You are not actually "consuming" much current at this point, but a lot of electrons are going back and forth through the breaker. Thus, even though your actual power

*consumption* may be less than 30 amps even when you are welding, you may need a much larger breaker -- unless you add power factor correction. With power factor correction -- basically capacitors wired up in a certain way -- you can reduce the circulating current considerably, allowing your breaker to be sized more in keeping with the actual current consumed.

Do the google search, and look especially for Gary Coffman's posts; he does a great job of explaining this -- what I have just said above is my (probably mangled) memory of what he said :)

I have a Dialarc 250HF and had similar problems when I tried to set the machine up in a friends garage for a temporary job. The inrush current destroyed two 30 amp breakers, one after another. We put my 50 amp breaker in and it worked OK. I have run the machine from 50 amp breakers and as long as you ignore the high range, it works fine. High range will zip the breaker every time and the top end of the medium range will do it occasionally (when you need it most). As long as you really have wiring and outlets rated for 50 amps, the machine will run on a 50 amp breaker. My advice is to leave the grounds connected to ground.

If you are doing stick welding, you should be able to weld 1/2" plate just fine. TIG is another story, but I am not sure the Dialarc 250P is set up for TIG anyway.

Good Luck, Bob

Assuming the welder was working, the 30amp breaker is likely too small. As mentioned above, power factor correction capacitors (assuming the Dialarc 250P doesn't have them) would reduce the inrush current needed. They are easy to add and inexpensive from surpluscenter.com. For a

250amp welder, you should be able to get the inrush current down to 10amps or so, idle current down to 5amps or so. If this is something you want to do, please reply and I will detail the steps for you.

However, if it wasn't working and you are fixing it, there are other possiblities. I would get a clamp-on ammeter that has peak-hold (it will also be useful to determine how much power factor correction capacitance to add above). And download, if you haven't, the Miller manual from their website.

Hook the ammeter (with peak-hold) to one of the power leads and do a test power-cycle. If the ammeter reads only slightly above 30amps, the small breaker is likely the problem.

If it reads above 40 amps or so, it is possible one or more of the main diodes are shorted (or something else is shorted). Disconnect the secondary side of the main transformer to remove the rest of the welder from the circuit and try again. If the breaker holds, start adding other components into the circuit to isolate which one is shorted. Or the problem could be in the control transformer/circuit. With the manual, you should be able to isolate suspect components. But, my first suspicion would be the main diodes.

Good luck.

I had a Miller Dialarc 250 HFP (with power factor correction). If I recall the manual actually stated something like 90amps at max current draw.

Anyway, I had the same problem as you in that a 30 amp breaker would "pop" when it started. So I simply just put in a new circuit. I decided to run #2 gauge copper. I was a little leery in being able to run this thick wire through conduit, but I found out that #2 copper is pretty flexible and suprisingly easy to handle. After that I put in a

90amp breaker (which is kind of funny in that my house has only a 100amp service).

Also, I mistakenly decided to use 4/0 grounding and electrode welding cables (which I had laying around), but this is definitely overkill and quickly changed them after welding a couple of times. They are simply way too cumbersome and heavy to manipulate when welding. So I went out and bought 1/0 welding cables and they are much more comfortable. I still think for my use, I could probably go even smaller on the welding cables, since I would only probably be at most 20 feet from welder and plus 20 feet back to the subpanel. Which would make welding even easier.

Aloha, Russell

My "new" mig welder says 60 Amp fuse on the front panel, I don't have that in my workshop/garage (yet!) just normal British 13Amp outlets. but just to check it works I crammed the wires into a 13Amp fused plug and hey presto it turns on and I can weld, at least with thin wire and a low volt setting.

Unless it's something to do with the type of transformer (does a stick/tig constant current transformer have a bigger inrush current?) I suspect your welder has a problem. Or I could be and probably am talking out my arse!

hope you get it sorted out Chris

A Miller 250P has power correction caps in the primary circuit. Typically, these caps can draw as much as 50 amps or more when welding machine is idling.

Find a way to bypass these power factor caps, or get a larger electrical service.

Good Luck

brad

I was under the impression that power factor caps reduced idling current?

Gunner

"At the core of liberalism is the spoiled child - miserable, as all spoiled children are, unsatisfied, demanding, ill-disciplined, despotic and useless. Liberalism is a philosphy of sniveling brats." -- P.J. O'Rourke

If I understand correctly, the power correction capacitors reduce *idle* current, but they result in a higher initial surge current when the machine is first turned on.

It might be worth investigating the breaker...

Breakers are available in different classes, I believe A-D, which alter the trip curve as to how long they will hold a surge load.

If your breaker is meant for loads like household electronics, a breaker meant for motor loads might hold.

Stuart

Power factor caps will reduce the current both when idling and when welding. When welding the reduction in current will not be significant.

I am a bit confused by all the talk of inrush current. We are talking about welders not motors. I don't think the inrush current is significant for welders, with or without power factor correction caps.

Dan

Idle current is not a big thing on these machines. 2-4 amps at idle seem typical for a non-capacitor machine.

50-60 amps are not unusual for a power factor equipped machine.

There are different types of draw on primary power. As it is explained to me, the draw on a pf capicitor equipped machine is of a different type of power that does not show up on the electric bill.

I'm sure one of our electrical guru's can further explain.

Good Luck

brad