Multiple 240V Outlets On one Circuit

[Rod Sheridan]

The required protection for the circuit will be the rating of one receptacle, so if you have 6 X 20A receptacles on a circuit, you need a maximum of a 20 ampere breaker.........Rod.

P.S. The maximum continuous load on the above circuit would be 16 amperes...............Regards, Rod.

[Rick Christopherson]

Yes....it's definitely not code or good practice to run multiple 240 receptacles on one breaker unless your wire and breaker upstream are rated for the combined loads.

This is not correct. You shouldn't tell people something is or is not code compliant when you are not knowledgeable with code. That leads to misinformation which gets perpetuated by others reading it and thinking it is stated factually.

The NEC does not distinguish between 120 and 240 volt circuits, and you are permitted to place multiple outlets on either type of circuit. Furthermore, the receptacle needs to match the circuit size. The exception being that you are permitted to use 2 or more 15-amp receptacles on a 20 amp circuit. Same as it is with 120 volt circuits.

[Rick Christopherson]

I need two 40 amp outlets and two possibly three 30 amp. in my basement shop.

Now I recall reading this thread a couple weeks ago, but didn't respond back then. First off, you cannot have 30 and 40 amp receptacles on the same circuit. A 30 amp circuit must use 30 amp receptacles (no exceptions). A 40 amp circuit may use 40 or 50 amp receptacles. There are some exceptions for arc welders, but because those were not listed in the question, I won't go into them.

However, the first question that popped into my head 2 weeks ago when I read the original question was why do you have so many high demand loads. There is nothing wrong with that. It is just unusual for a woodworking forum, and raised some red flags with me. (Forgive me if this was answered later in the thread. I did not re-read the whole thread.) For woodworking tools, a 20 amp circuit can handle up to a 4 hp motor that is not a continuous load. A 30 amp circuit can likewise handle 6 hp, and a 40 amp circuit 8 hp.

Woodworking power tool instruction manuals, especially those from Grizzly, have a habit of incorrectly stating circuit size. If this is the reason why you believe you need circuits or receptacles this large, then you should re-evaluate the need.

Again, my apologies if this was covered previously. I read this thread 2 weeks ago, but did not re-read it today.

Edit: By the way, most woodworking tools are not considered continuous loads because they operate for short periods. Furthermore, most woodworking tools do not operate at full rated capacity for more than a few seconds at a time. For these reasons, they do not fall under the 80% rule for circuit loading or receptacle loading. This allows them to draw up to 100% circuit or outlet ampacity.

[James White]

Rick,

Thank you for the info. I ran a 40amp circuit for my Woodmaster 25" planer (7hp) and ark welder. The other three machines are 3hp and I thought they needed 30 amp circuits. Yes they are Grizzly machines. I suppose I may have gotten that requirement from them. Now that they are ran. Should I reduce the breakers to 20 amp.? Is that o.k. to have with the 30amp receptacles? I do not think the 3hp machines have built in protection. I could be wrong on that though.

James

Now I recall reading this thread a couple weeks ago, but didn't respond back then. First off, you cannot have 30 and 40 amp receptacles on the same circuit. A 30 amp circuit must use 30 amp receptacles (no exceptions). A 40 amp circuit may use 40 or 50 amp receptacles. There are some exceptions for arc welders, but because those were not listed in the question, I won't go into them.

However, the first question that popped into my head 2 weeks ago when I read the original question was why do you have so many high demand loads. There is nothing wrong with that. It is just unusual for a woodworking forum, and raised some red flags with me. (Forgive me if this was answered later in the thread. I did not re-read the whole thread.) For woodworking tools, a 20 amp circuit can handle up to a 4 hp motor that is not a continuous load. A 30 amp circuit can likewise handle 6 hp, and a 40 amp circuit 8 hp.

Woodworking power tool instruction manuals, especially those from Grizzly, have a habit of incorrectly stating circuit size. If this is the reason why you believe you need circuits or receptacles this large, then you should re-evaluate the need.

Again, my apologies if this was covered previously. I read this thread 2 weeks ago, but did not re-read it today.

Edit: By the way, most woodworking tools are not considered continuous loads because they operate for short periods. Furthermore, most woodworking tools do not operate at full rated capacity for more than a few seconds at a time. For these reasons, they do not fall under the 80% rule for circuit loading or receptacle loading. This allows them to draw up to 100% circuit or outlet ampacity.

[James White]

Woodworking power tool instruction manuals, especially those from Grizzly, have a habit of incorrectly stating circuit size. If this is the reason why you believe you need circuits or receptacles this large, then you should re-evaluate the need.

I did feel kind of duped. When I was installing 10awg cords in the machines junction box. When the internal wires for the relay where tiny in comparison. I would like to guess at about 14-16awg.

James

[Scott Driemel]

Hello James. I'm in the middle of wiring my shop and just had this discussion with my electrician after he contacted the inspector. (This is in the Vancouver BC area) I have 3 40amp welders, a ac/dc, a mig, and a tig. I wanted them all hooked up (as in plugged in) so I didn't have to look for cords and re & re them each time I wanted to switch a welder. I thought a single drop with 6/3 wire, yup, cause one welder says 47.5 amps on it, I could them split it off into 3 boxes. Easy peazy I thought. Inspector said, because there is the REMOTE chance that someone "down the road" might try using two welders at once, I have to either run 1 only plug, or run a 50amp breaker & 6/3 wire to each of the 3 plugs. Ridiculously expensive at $14.99 / meter for the 6/3 wire. He said, he'd "consider" a splitter box that was basically a switch box that would only allow one of the three plugs to be turned on at once. (I'm awaiting a quote on the cost of such a box) I asked then what about my multiple 20 amp 240v machines as I was going to run a single line with multiple (well 3 anyways) drops off? He said again, he'd ONLY allow 1 plug per circuit. I again stressed I'm a one man hobby shop but he went on about the "what if's) down the road if someone else tried to run multiple machines. I said well the breaker would blow then. He says "yes, but if the breaker malfunctioned, it "could" start a fire. I'm now going to have to run a seperate 20 amp circuit and breaker to EACH plug if I want to leave my machines plugged in for convience.
I agree with other posters how this seems wrong as that it doesn't apply to 120v circuits inside a home. Seem to running in circles, I hope you get a solid answer on this but perhaps in the USA it might be more reasonable. Best of luck James!

[Rick Christopherson]

Hello James. I'm in the middle of wiring my shop and just had this discussion with my electrician after he contacted the inspector. (This is in the Vancouver BC area) I have 3 40amp welders, a ac/dc, a mig, and a tig. I wanted them all hooked up (as in plugged in) so I didn't have to look for cords and re & re them each time I wanted to switch a welder. I thought a single drop with 6/3 wire, yup, cause one welder says 47.5 amps on it, I could them split it off into 3 boxes. Easy peazy I thought. Inspector said, because there is the REMOTE chance that someone "down the road" might try using two welders at once, I have to either run 1 only plug, or run a 50amp breaker & 6/3 wire to each of the 3 plugs. Ridiculously expensive at $14.99 / meter for the 6/3 wire. He said, he'd "consider" a splitter box that was basically a switch box that would only allow one of the three plugs to be turned on at once. (I'm awaiting a quote on the cost of such a box) I asked then what about my multiple 20 amp 240v machines as I was going to run a single line with multiple (well 3 anyways) drops off? He said again, he'd ONLY allow 1 plug per circuit. I again stressed I'm a one man hobby shop but he went on about the "what if's) down the road if someone else tried to run multiple machines. I said well the breaker would blow then. He says "yes, but if the breaker malfunctioned, it "could" start a fire. I'm now going to have to run a seperate 20 amp circuit and breaker to EACH plug if I want to leave my machines plugged in for convience.
I agree with other posters how this seems wrong as that it doesn't apply to 120v circuits inside a home. Seem to running in circles, I hope you get a solid answer on this but perhaps in the USA it might be more reasonable. Best of luck James!

I am not an expert on Canadian Code, but it is fairly similar to U.S. code with some exceptions. It is not unusual for an inspector to overstep his authority, even when he is dealing with a licensed electrician. I am guessing that this is not Canadian Code, and if you asked your inspector (under your legal right to do so) for the code citation for his ruling, he will quickly back off, because he cannot (at least in the U.S.) provide it.

In the U.S., under most State Constitutions, the inspector is not the authority having jurisdiction, and he cannot impose requirements that are not written into local law. The NEC is not automatically local law, but is only "adopted" into law by the State Board of Electricity. One of the most common sources of misinformation on wiring is when a local inspector oversteps his legally prescribed bounds with a homeowner or even electrician, because he knows he can get away with it if they don't challenge him.

State Constitutions prevent this very thing from ever happening. The analogy I use frequently for this is that without this protection, a police officer could decide that driving a blue car on Tuesdays is against his personal law. The State's Constitution prevents this from ever happening. Just like a police officer cannot change the local law at his whim, a state electrical inspector cannot change the law at his whim. The NEC is not a law by itself, but the State chooses to adopt the code "as law" with or without amendments.

[Curt Harms]

Hello James. I'm in the middle of wiring my shop and just had this discussion with my electrician after he contacted the inspector. (This is in the Vancouver BC area) I have 3 40amp welders, a ac/dc, a mig, and a tig. I wanted them all hooked up (as in plugged in) so I didn't have to look for cords and re & re them each time I wanted to switch a welder. I thought a single drop with 6/3 wire, yup, cause one welder says 47.5 amps on it, I could them split it off into 3 boxes. Easy peazy I thought. Inspector said, because there is the REMOTE chance that someone "down the road" might try using two welders at once, I have to either run 1 only plug, or run a 50amp breaker & 6/3 wire to each of the 3 plugs. Ridiculously expensive at $14.99 / meter for the 6/3 wire. He said, he'd "consider" a splitter box that was basically a switch box that would only allow one of the three plugs to be turned on at once. (I'm awaiting a quote on the cost of such a box) I asked then what about my multiple 20 amp 240v machines as I was going to run a single line with multiple (well 3 anyways) drops off? He said again, he'd ONLY allow 1 plug per circuit. I again stressed I'm a one man hobby shop but he went on about the "what if's) down the road if someone else tried to run multiple machines. I said well the breaker would blow then. He says "yes, but if the breaker malfunctioned, it "could" start a fire. I'm now going to have to run a seperate 20 amp circuit and breaker to EACH plug if I want to leave my machines plugged in for convience.
I agree with other posters how this seems wrong as that it doesn't apply to 120v circuits inside a home. Seem to running in circles, I hope you get a solid answer on this but perhaps in the USA it might be more reasonable. Best of luck James!

Scott, it might be a sub-optimal solution but how about an "extension cord" plugged into your one allowed outlet and multiple outlets on that extension cord?

[Ron Natalie]

Interior ("fixture") wiring is allowed to be smaller than the building wiring for a number of reasons. No need to feel "duped"

[Scott Driemel]

hmmm, Curt that's pretty crafty! But, I recently watched a show on the Insurance Industry for travelers. Although in the program, 80% of them had travel insurance, when they examined it, only 25% would have actually been allowed the claim! Seems we don't read the small print. The story showed that if you failed to disclose you were on a medication for say a sinus infection, and you were hit by a car in another country, your claim would be denied and you'd be out the full (potentially hundreds of thousands) amount. Because you failed to by ignorance or wilful intent, disclose this. EVEN if it wasn't anything to do with your accident. This was one of the largest insurance Co's in North America. That being the case, if you ever had a claim, (a big one, say house burnt down do to a faulty kitchen appliance) and they discovered your "pigtai" they could, (according to the expose they would) deny your claim even though it had nothing to do with the other. I'm too concerned to gamble, no offence to any insurance sellers out here on the forum, but it seems it's primary focus on occasion is to deny rather than allow a claim. It was after this program, just on in the last month, that made me go the whole "inspection" route.

[Andrew Joiner]

hmmm, Curt that's pretty crafty! But, I recently watched a show on the Insurance Industry for travelers. Although in the program, 80% of them had travel insurance, when they examined it, only 25% would have actually been allowed the claim! Seems we don't read the small print. The story showed that if you failed to disclose you were on a medication for say a sinus infection, and you were hit by a car in another country, your claim would be denied and you'd be out the full (potentially hundreds of thousands) amount. Because you failed to by ignorance or wilful intent, disclose this. EVEN if it wasn't anything to do with your accident. This was one of the largest insurance Co's in North America. That being the case, if you ever had a claim, (a big one, say house burnt down do to a faulty kitchen appliance) and they discovered your "pigtai" they could, (according to the expose they would) deny your claim even though it had nothing to do with the other. I'm too concerned to gamble, no offence to any insurance sellers out here on the forum, but it seems it's primary focus on occasion is to deny rather than allow a claim. It was after this program, just on in the last month, that made me go the whole "inspection" route.

Scott, I agree it's hard to trust the insurance companies. BUT,
if they really could get out of paying that easy , no one would ever collect on any fire damage. Really no building is perfect inspected or not.
read this thread:
http://www.sawmillcreek.org/showthre...-and-Shop-Heat

Post # 6 is by an insurance agent and it makes sense, he says:
"​Insurance contracts are unilateral. Meaning once they offer insurance to you they are on the hook, unless there is a "material misrepresentation on your part" or you don't pay the premium.

As an insurance agent I get this question asked to me a lot. The truth of the matter is that we are representatives of that insurance company. If they misrepresent the insurance company then they are opening themselves up to an Errors and Omissions claim."