Internet BS a Formidable Hindrance to DIY Electricians

I didn’t have much time to work on the workshop today, but I got some good things done.

I want to get my remaining machinery moved in, so I need to have 250V outlets in various locations. When I moved here, there wasn’t a one. I slapped a couple together, along with a new subpanel, right before Hurricane Dorian passed by, and since then I have replaced that subpanel with a better one and added a number of outlets.

Today I put 50-amp and 20-amp outlets up, just below the subpanel. These replace two outlets that were attached to the old subpanel. They will give me more flexibility in tool placement.

I now have one 50-amp outlet by the west garage door and one about halfway down the north wall. I expect to move my welding operations all the way down the wall, so I don’t think I’ll have much use for the new 50-amp outlet once all the wiring is done, but I will need it until I get the ones farther down installed, and I may drill through the wall and connect it to a new outdoor outlet, to connect to a generator. Besides, it never hurts to have another outlet.

I’ve decided what do to about the south wall of the shop. I’m going to run 6/2 Romex across the trusses and down the wall to a junction box. From that box, I will make one run to my table saw, which will get 50 amps, and another run to the general vicinity of the band saw, which gets 20 amps. If I need more 20-amp outlets, I can connect them to the band saw’s outlet. That type of outlet permits you to connect several in parallel.

The last circuit will be 50 amps to the southwest corner, for a compressor. I could get by with 20 right now, but I may want a bigger compressor later, with a 7.5-HP motor. I don’t think a 7.5-HP compressor really needs 50 amps, but it’s usually a good idea to run big wire when you have the choice. I can always add new outlets to the same circuit if I want.

I may run heavy wire to a 20-amp receptacle for the compressor and connect it to a 20-amp breaker instead of using a 50-amp breaker. The compressor already has a 20-amp plug on it. If I move to a bigger compressor later, I can just change the breaker and receptacle.

It’s funny, but people say two things which are very inconsistent. They say you should always go with a big circuit breaker and heavy wire, and they also say you shouldn’t plug a machine into a socket that supplies way more current than it needs. Obviously, you can’t have it both ways.

People like to say that if you put, say, a 20-amp machine on a 50-amp circuit, you risk having a fire downstream if there is a short in the cord or machine, so you should use a smaller breaker. Well, then…if that’s true, why would you have a practice of using large breakers to play it safe? It makes no sense. A large breaker will permit more current to flow. If the breaker is supposed to protect the machine and cord as well as the wiring, you want the smallest breaker that will run the machine.

The purpose of circuit breakers is to protect wiring, not electrical devices. If you’re worried about your machine burning up, you should put a breaker on the machine. This is why many products come with breakers and fuses built in.

There is nothing safe about a big breaker. The bigger a breaker is, the less safe it is.

The purpose of heavy wiring is to reduce heat due to resistance caused by high current draw. The purpose of a breaker is to limit current draw and, therefore, heat in the wiring. The machine is on its own. Our houses are full of stuff that can fry at 125V on 20 amps or even 15, yet we don’t run around unplugging everything at night. If I had to think about a machine’s size every time I moved it down the wall to a different outlet, I’d be redoing circuits all the time. No one does that. Maybe OSHA or the electrical code people require it in commercial shops. I don’t know. But it’s impractical in a home workshop.

Sometimes I think I should never ask anyone for advice on the Internet. They come up with a lot of bad ideas.

You have to have a big enough breaker to supply your machines, with wire so heavy it won’t overheat at the breaker’s operating limit. You don’t need giant breakers and wires like garden hoses for all your 250V outlets.

Here is how I see it: big wires are never a bad idea, unless they’re too thick to install. Big breakers can be a problem if the wire isn’t matched to them. If you’re worried your machines will burn up, you should have some kind of protection built into each one instead of relying on your building wiring to do a job it was never designed to do.

I think this is right, and I plan to govern myself accordingly until someone gives me a good reason to change my mind.

I think the best protection I can have is to shut off the juice to the machinery circuits when I leave the shop. I don’t think I’ll do it, though. I don’t really see my band saw, for example, bursting into flame at 2 a.m. for no reason.

Tonight I bought 125 feet of 60/2 Romex. I’m sure 8/2 would have been fine, and I wasn’t planning on using more than 65-70 feet right away, but I decided to err on the side of safety, and 125 feet of prepackaged wire was about the same price as 70 feet of cut-to-order. I feel like I got 60 or so feet for nearly nothing. I was only planning to do the run in the table saw area this week, but now I have enough wire to do the compressor run as well.

Maybe I’ll hang the Romex tomorrow. That will tell me how much conduit to get. I don’t look forward to using the ladder, which is heavy, but it will be nice not having to run much conduit. Going over the trusses with bare Romex will be a lot less aggravation.

This is where things stand tonight. I think I deserve a couple of hours of Youtube.