Routing 240v 50A around I-Beam

[sberry]

Parts of a 30A heater may be fine but not all on 50, some of the main wire but some controls and wire need the current limit of the 30, doesn't have further internal fuses for it (like the Xmas lights or power strip].
When we see a statement like,,, the breaker only protects the circuit wire not the appliance ce it is only partially true and in some,, many cases not true at all. A lot of equipment depends on the breaker,, most of it not for thermal but for fault. Breakers are for thermal like 120v that have multiple outlets, let's say 10 outlets on a circuit where someone can come along and plug more than one heater to it, would overheat the wire. With 1 outlet or hard wired not such a concern, when hard wired it's up to the installer to consider all these compliance factors.
Wire instructions for welders, other equipment are written for people they assume understand this, lic electricians are spozed to.

 

[sberry]

I believe a guy can get thru elect engineering school without cracking a code book. The welding machine companies hired some who are brilliant and likely to be more electronic than electric of old and the understanding of cords and breakers lacks in some. They are genius but never read the book in that area enough for it to become second nature of good electricians. They have help, they have nema, they get it right but ask some about how to (they are usually safe] but they really don't know.
This is not all of them but have seen it. Always remember, you can get 30% of the answers wrong on the test and still pass. Ha. Might even be answers to some of the most important questions.
I took a test a while back was designed due to this. Several of the questions designed so if a guy didn't understand a basic principle would really tank the score as you would get all them wrong.
Electrician trainING and testing designed to insure the guy does understand, he may get some wrong but has fundamental principles instilled.
I got by a long time without knowing, my mechanical design and install and even the ability to land wires in the right spot hid the fact I didn't know. This is the area I tend to focus on the forums. The higher tech doesn't interest me so much, most of it wayyyyy over my head.

 

[sberry]

I can spot it on a couple welding forums. I ask, where did you learn this. They been doing it for 40 years. Some been doing it wrong, some right even though the understanding is rudimentary.

 

[u2slow]

If you're running conduit over to this location, why not install a subpanel at the location? You'd only need to run a single circuit through the conduit to feed the subpanel, and then you can run separate circuits from there to the compressor and heater.

This works well. I have a double wall-oven away from the kitchen I needed to feed. (~20A each) so I brought #6 over to a sub with a 2P30A for each oven, and an extra circuit for misc receptacles nearby. I'm copying this strategy for the far end of my shop. Going to use #8 for now. May increase it to #6 when I make it permanent.

The motor is a Dayton 9TC62A and you are correct, it lists HP SPL and not as 5 HP (don't know where I got that idea)

Believe it to be the original motor on this 1999 Speedaire 20 gallon compressor.

The plug has this 6-20P configuration only its molded as part of a 14/3 STO cord.

I have a similar speedaire with the 6-20p. 20A circuits are handy.... with only two #12/3c feeds, I've run all the tool loads in my 1-man shop for the last 5 years.

I don't like the rules around electric heat. In my jurisdiction, I can marry a bunch of smaller (installed) baseboard heaters onto a larger circuit; I can even 100% the loading on the wire, and 125% the breaker size for certain situations. (Reason being the failure condition for a resistive heating load is open-circuit, and the heaters have thermal overloads.) But when its a portable unit, that doesn't fly - the 'heater' receptacle could get used with a different tool/appliance.

I suspect the manufacturer calls for a 30a circuit for it and thus a 50a circuit will not work.

Oh it works... lol! ...but you knew that

 

[u3b3rg33k]

It's because the appliance that's plugged into a 30A receptacle SHOULD use only 30A max, but what if the appliance malfunctions and it starts drawing more than that? The breaker will trip if it goes over 50A, but what if it stays at around 40A?
The receptacle can only handle 30A. It can start to melt, burn and start a fire and the breaker will never trip to stop it.
An appliance that draws 4A can be plugged into a 15A receptacle because the receptacle can handle 15A, and it's on a 15A breaker. If the current goes above 15A, the breaker tops before any damage happens to the receptacle.

in general, a 14-30 and a 14-50 have the same internals (at least based on my observation). just different keying. also a 6-30 actually has bigger contacts than a 6-50. they come as a combo plug and you use the blades for your application. typically, a 6-30 is for a heater, so one expects continuous load. 6-50 is typically for welders, which are intermittent load.

this can happen on any circuit if wires are loose, ampacity notwithstanding:

 

[sberry]

If the appliances were not limited then we would use heavy recepts and simply plug in to 100 service and forget the breakers. It is kind of a simple concept to assume it's just to protect the recept from overheat, while that is somewhat true it's not really what it's about,,, hence the burned recept without the breaker tripping most of the time. The equipment itself isn't designed to be plugged in to heavier circuits, as an example above, 14 cord, molded 20A end.

 

[sberry]

I have seen 6/50 used on pottery kiln, I don't think it was factory. When the installer does this he is to check the wire size. If it's a 14/50 it's good to go in theory as undersized wire isn't allowed with that recept. Same for old range recept.

 

[u3b3rg33k]

I *think* you can undersize 14-50 for 40A breaker/wire. you can undersize a 6-50 for welder duty.

I make the assumption that everything is wrong until proven otherwise.

 

[sberry]

Yes, spose you might with smaller breaker.

 

[ZeeResto]

Thanks everybody who replied.
To follow up and close, I just ran both the 20 AMP and 30 AMP wiring behind the 4x2" framing notched and metal-plated.

Had enough access above the common wall between the garage and the basement living area to run my cables. For both circuits, I just came out at the tops of the wall paneling, adding surface mounted boxes for each appliance )shop heater and air compressor).

Simple. (although it took a lot of prying to get it into my head!)