220vac(230/240/250v?) breaker & receptacle questions

[working on it]

I'm asking this question over here, in Electrical Secrets, not in Trailer and Chassis, since it may be perused by an electrical wizard. I am not too knowledgeable about AC current (and wary of 220v and higher, having been bit by 480v before at work), so I try to avoid anything over 110vac (115/120) if I can. I used GFCIs and surge strips instead of breakers in my trailer, because of that. Well, anyway, her is my question, also trailer-building-modding related: I bought a cheap stick welder "230vac", though advised not to http://www.tnttt.com/viewtopic.php?f=35&t=23778&start=45#p1050404, though assured by a welder at work that his identical unit at home is great. I put the cart before the horse (as usual for me), and never checked my garages' 220/230/250vac plugs and breakers (never needed by me, buried for 20 years behind storage racks). I knew the guy I bought the house/garage from had a welder and other shop equipment there, but I only needed 110/115/120vac until now. There is a sub-panel with two 20amp single breakers, and one double 40amp breaker.

20a,20a,40a garage panel.jpg (41.61 KiB) Viewed 2871 times

The 20amp singles are for the lower voltage, and the 40amp double is for the higher voltage, right? But here's the receptacles coming from the 40amp breaker

wall receptacles.jpg (70.18 KiB) Viewed 2871 times

(Please excuse the cobwebs, etc.; been unused/covered up for twenty years-needs cleaning). If I read the charts correctly, then the receptacles are not what I need: a 6-50R (like this) to match the welder plug.

6-50R.jpg (38.75 KiB) Viewed 2871 times

The welder data specifies that max input current is 41amps at 180amps welder output (at duty cycle limit). I've already reduced and marked the setting gauge on the welder to 150amps max output, so I should neither trip the 40 amp breaker nor limit myself to the 10% duty cycle (no matter there, I can't see a need to weld for over a minute at a time anyway); I have lots of time. Am I within the acceptable limits for the system here? I want to just change one of the 6-20R or 6-30R receptacles to the 6-50R just for welding. I have no plan for other 220v and up equipment, ever. If I do, in the future, I'll get an electrician to re-wire it all.

[48Rob]

I want to just change one of the 6-20R or 6-30R receptacles to the 6-50R just for welding

The breakers protect the wire.
The wire in your photos does not appear to be large enough to carry the draw.
Having a pro install a properly sized and protected circuit is the only option I would suggest.
Much cheaper than a fire.

Rob

[working on it]

I want to just change one of the 6-20R or 6-30R receptacles to the 6-50R just for welding

The breakers protect the wire.
The wire in your photos does not appear to be large enogh to carry the draw.
Having a pro install a properly sized and protected circuit is the only option I would suggest.
Much cheaper than a fire.

Rob

I sorta figured that the cable was not up to code, if it is Romex (have to get a closer look). It was put in in '78-80, long before the color of Romex was standardized (maybe even before a code ???). I'll heed your warning, and either get an electrician over or get my wife's cousin (electrician, out of state) to advise my course of action. I'm going to take my time and get it right for once (electrical jinx for years).

[eggsalad]

Depending on the length from the panel to the receptacle, you will want 8 gauge or maybe even 6 gauge wire. 220VAC is not a place for amateurs to play. If it's a short and straightforward wire run from the panel to the receptacle, a Licensed Electrician would get $150 max for a quick, but trustworthy job.

I know that folks at TNTTT are a thrifty bunch, but this is not the place to save a buck.

[eamarquardt]

Depending on the length from the panel to the receptacle, you will want 8 gauge or maybe even 6 gauge wire. 220VAC is not a place for amateurs to play. If it's a short and straightforward wire run from the panel to the receptacle, a Licensed Electrician would get $150 max for a quick, but trustworthy job.

I know that folks at TNTTT are a thrifty bunch, but this is not the place to save a buck.

No household wiring is "a place for amateurs to play". However as I suspect that virtually all household electrocutions are between a hot (120 volts) and ground, a 240 volt circuit (two 120 hots 180 degrees out of phase with each other) is no more dangerous than a 120 volt circuit other than you have two hot wires in a 240 volt circuit rather than just one in a 120 volt circuit.

That said, you have to check and see how big the breaker serving your sub panel is. It, and the wiring it protects, may not be robust enough to support your welder. When I installed a sub panel in my garage I wired it for 100 amps. Glad I did as I've tripped an 85 amp breaker on several occasions when putting the "pedal to the metal" on my TIG machine.

Cheers,

Gus

[eamarquardt]

Depending on the length from the panel to the receptacle, you will want 8 gauge or maybe even 6 gauge wire. 220VAC is not a place for amateurs to play. If it's a short and straightforward wire run from the panel to the receptacle, a Licensed Electrician would get $150 max for a quick, but trustworthy job.

I know that folks at TNTTT are a thrifty bunch, but this is not the place to save a buck.

No household wiring is "a place for amateurs to play". However as I suspect that virtually all household electrocutions are between a hot (120 volts) and ground, a 240 volt circuit (two 120 hots 180 degrees out of phase with each other) is no more dangerous than a 120 volt circuit other than you have two hot wires in a 240 volt circuit rather than just one in a 120 volt circuit.

That said, you have to check and see how big the breaker serving your sub panel is. It, and the wiring it protects, may not be robust enough to support your welder. When I installed a sub panel in my garage I wired it for 100 amps. Glad I did as I've tripped an 85 amp breaker on several occasions when putting the "pedal to the metal" on my TIG machine.

Cheers,

Gus

[working on it]

OK, good news and bad news...good news is that I uncovered and traced all cables and circuits to my garage/shop and outbuilding. The bad news is it is all wrong. First, the feed from the outside power pole (leaning and loose in the ground, can't put off fixing that any longer) to both locations isn't armored, nor is it any different than the 12AWG three-wire cable in the garage (I was barely able to make out the ID). Second, the breaker in the outside power pole is a 50amp, which leads to both the garage and the shed (two sets of wires to one breaker). The shed (which only has 110vac, has a 30amp breaker, and three 15amp receptacles). The garage, as detailed before, has the 20amp and 30amp 220vac receptacles off of a 40amp breaker, and ten 15amp receptacles for 110vac, from two single 20amp breakers. All garage wiring is the same 12AWG cable everywhere. I guess I've been lucky to spot this mismatch mess now before a fire (it's only been twenty-one years since we moved in). I've had wiring problems since Day One, in the house, so I was satisfied that there had been none outside (except for the sanded up and ground-faulted well, long forgotten), so I didn't look for any problems. I've had so many problems at work for 44 years, taking most of my attention, that I willfully have overlooked some here at home. If I hadn't bought the 220v welder, I may not have ever looked at all. Funny thing though, the previous owner/builder was a contractor, and the power company and two other electricians have been here in and out, several times over the last two decades...no one knew what they were doing, I presume. If it ain't broke, doesn't mean it won't need fixing!

[48Rob]

Funny thing though, the previous owner/builder was a contractor, and the power company and two other electricians have been here in and out, several times over the last two decades...no one knew what they were doing, I presume. If it ain't broke, doesn't mean it won't need fixing!

Most contractors take pride in doing things the right way, or not at all, but there will always be some that will do whatever, because they either don't know any better, or think it is okay to do a half baked job since it "is for them".

Your quote is right on!
Just because something that was poorly done, either intentionally, or through ignorance hasn't failed, started a fire, or hurt someone doesn't mean it is safe, or right...

Glad you caught the issues. While it has worked okay with minor loads over the years, overtaxing the system with your welder could have been the last straw.

Rob

[H.A.]

.

[working on it]

To split hairs,
The receptacle on the right is a NEMA 6-15R.
NEMA 6-30R is substantially larger and wont fit within a singlegang box.

As others stated, You need to verify the circuit feeding your garage panel is large enough to supply your new welder, PLUS whatever existing loads, lighting, appliances, etc.
It appears you have a 100amp Square-D Loadcenter, However, does not mean it is supplied by a 100amp circuit.

Just trying to identify things using the internet, not from experience....The garage loadcenter, with 8 slots, is supplied from the main power pole thru a 50amp breaker (and 30amp incorrect cable); the house is fed thru a 100amp breaker (much thicker cable), and the central air (now not used) has it's own 60amp breaker (and thicker cable). I think/hope that the house was wired and checked by pros at one time, while the garage & shed were done by the past owner with leftover parts. I'll never know, but I'm going to have all inspected at long last.

[MtnDon]

[quote

Most contractors take pride in doing things the right way, or not at all, but there will always be some that will do whatever, because they either don't know any better, or think it is okay to do a half baked job ...

Well, there are contractors and then there are Contractors. I have seen too many jobs here in NM done by people who called themselves contractors to be surprised by sub par work. Many of them are not licensed but even some that are have poor understanding of what is right/wrong or specified by building code. They get away with it because they can. The system can't keep up... But then at times I believe there is too much system... Need a happy medium. But that is another rant...

[48Rob]

Don,

I hear you...

As I am a contractor, I like to think there are more good than bad, but the field has always been "open" for less than skilled opportunists.

Rob

[eamarquardt]

I've found that with a little effort one can find out for themselves how something should correctly done.

I've had all the work I've done on my various homes permitted and inspected (cheap insurance). The building inspectors have usually been impressed with my "overkill in moderation" approach.

Rarely am I truly impressed with "professional" work.

A while back I questioned/challenged the owner of an automotive machine shop who has been in business for thirty plus years. He stated that the threads for the oil pressure sender on air cooled VW block were 1/8 npt. I told him that I thought they were metric and 10 (or 12) X 1. Soooooo, he got out a pitch gauge and confirmed my thought. He then said: "Darn, I've been doing this wrong for 30 years". I was impressed with his willingness to listen and learn from an "amateur" as most "professionals" I've questioned try to BS their way out of it.

Spend some time learning what should be done to make it right and then, regardless of who does the work (you or a "professional"), you'll know it was done correctly.

Good luck,

Cheers,

Gus

[GerryS]

Now that's a mechanic I would trust. I don't mind wrong, we ALL make mistakes, or just have bad data between our ears. The willingness to learn something new is the important part.

The thing is, even people who are genuinely wrong about a particular skill, may have an insight not directly related that you can use, or at least spark an idea you wouldn't have had otherwise.

[working on it]

To split hairs,
The receptacle on the right is a NEMA 6-15R.
NEMA 6-30R is substantially larger and wont fit within a singlegang box.

As others stated, You need to verify the circuit feeding your garage panel is large enough to supply your new welder, PLUS whatever existing loads, lighting, appliances, etc.
It appears you have a 100amp Square-D Loadcenter, However, does not mean it is supplied by a 100amp circuit.

I forgot to acknowledge that H.A. was right, the receptacle was a 6-15R. Since I was home today, I did some more (closer) checking of the main panels and the cable/wiring leading to them. I pried and separated (very carefully) the 'tied, buried, wrapped' input wiring to the outdoor main from the output wiring to the shed and garage sub-panels. At closer inspection, I found I was wrong about the previous owner using 12ga indoor Romex going underground to those two panels. I found 8/2 cable instead. That's 8ga! The ampacity is good for 40 amps to both areas. The wire run to the shed panel is 75 feet to its 30amp breaker, and 30-32 feet to the garage panel with its 40amp breaker. After that point, the wire is only 12ga to the receptacles. Using this calculator http://www.csgnetwork.com/wiresizecalc.html, it shows that I could "get by" with only 12ga wiring (at the reduced output setting I set the welder to). If correct, I could go ahead and change one receptacle to 6-50R, and test the stick welder to the reduced setting. At worst case, the sub-panel breaker would trip (I will also check the fully-exposed 12ga wiring for elevated temperature as well). I still will have the electrician cousin consult, and check, and possibly re-wire the whole thing soon. I won't "use" the 220v welder till then, just the one "trip" test. I'll get the small 110v flux welder if I just can't wait.