240V receptacle preferences? And a boo-boo confession...

[Alex Zeller]

By code only 15a 120v receptacles can have multiple outlets on one run. If you have stationary equipment this isn't too much of an issue. If you move your tools around it usually means lots of cords. If you have 30 amp breakers then everything downstream from it also needs to be rated for 30 amps. If you choose not to follow code I recommend you make it so you can easily remove it if you sell your shop. I personally have two 30 amp runs with multiple 30 amp outlets because I know that I'll never use both receptacles at the same time. I also have short pigtails with a 30 amp plug and a 20 amp receptacle inside a metal box so I don't need to put 30 amp plugs on all my tools. But I'm a hobbyist and the only person who works in my shop.

[Tom M King]

I've had Hubbell receptacles, plugs, and cord ends in service for so long, that I forget which model they are. I did like Bill, and have a short tail on each tool. I have a fair number that have been in service since the mid 1970's. I did destroy one end, but that was because I forgot to unplug it before I drove off in the tooltruck stepvan. I sold that truck in the early 1990's. It was a 1970 model. I outgrew it.

[John Lanciani]

By code only 15a 120v receptacles can have multiple outlets on one run.

Can you provide a citation for this? I’m 99% sure that it is incorrect but my 2020 NEC book is 10 miles away.

[Frank Pratt]

By code only 15a 120v receptacles can have multiple outlets on one run.

This is the first time I've heard this rule. Can you tell us where it is, because I don't think that's right?

[Charlie Velasquez]

This is the first time I've heard this rule. Can you tell us where it is, because I don't think that's right?

Multiple receptacles are allowed in most cases, both 120 v and 240 v. There are some cases where a single dedicated outlet is required, as in a sump pump installation. There are some cases where multiple outlets are required, as 15 amp receptacles on a 20 amp 120 volt circuit breaker.
NEC 210.20’s discuss cases where branch circuits have multiple receptacles.

[Jack Llewyllson]

By code only 15a 120v receptacles can have multiple outlets on one run.

Nope. Despite the popularity of that opinion, I've found nothing in the NEC to support it. I believe this statement is incorrect.

I'm also quite certain that this topology is not a safety hazard in my shop. I'll never run more than two pieces of equipment at the same time, defined as (machine) + dust collector. The heaters are also on 240V, but they have their own 30 A circuit (both share a 30A circuit; they draw 3.8 amps each).

Also, I've run 2 ea., parallel, 240V tool circuits to make it easy to separate dust collection draw from tool draw. So if I'm running the planer, for instance, it'll be pulling from circuit "A," with the DC drawing from circuit "B."

Furthermore, it's not like the circuits are unprotected fire starters. Both of the tool circuits have circuit breakers in case of overload.

Overloading 30A circuits with my cute little tools is frankly unlikely. I could run the saw (12.8 amperes) and the planer (11.51 amps) on the same circuit, at the same time, provided I didn't start them simultaneously. If, however, I somehow managed to use up the circuit's ampacity, its breaker should trip well before the 10-gauge wire heats up in the wall.

Finally, while there are certain home-level use cases (e.g. water heaters and jacuzzis) where dedicated circuits are called out in the code, shop tools don't fall into that category AFAIK. The two inspectors who've looked over the rough-in so far didn't seem to think so, either -- and I asked. Better to get caught early than blow the sign-off when victory is in sight.

This dedicated circuit idea is a canard that everyone has heard, and which many believe. Not being an electrician myself, I spent a fair amount of time chasing it down to either confirm or debunk. I'm pretty confident that it's an authentic -sounding rumor, not a fact.

But don't take my word for it. I'm not an electrician.

[Bill Dufour]

Off the top of my head a refrigerator outlet must be the only one on that circuit and a washing machine may be on a non GFCI circuit. I do not think a dryer can run off that same non GFCI circuit unless it is at least 6 feet from a sink and the washer?
240 outlets can have multiples on one circuit. I think for 120 it is 12 receptacles per circuit maximum.
Bill D

[Marc Fenneuff]

I really like twist-locks and made up a couple pigtails for when I need to directly plug-in a vac or powered hand tool. I have them for my 120V and 240V tools.

[Bruce King]

The most recent locations where GFI is required is the dishwasher and laundry area.
If a dishwasher is hard wired, the circuit breaker has to be GFI. This is due to the finding that all the dishwasher fires start as current leakage that a GFI will trip on. Some new dishwashers might have an internal GFI with the reset at the lower front. The circuit still needs one too since no one knows which unit will be installed. Many houses have a wall switch for the dishwasher, this was the 1980’s effort to stop some dishwasher fires. All idle dishwashers should have the switch off or the door cracked open for safety. These units are total garbage when it comes to internal wiring safety.
The language about 6 feet has been changed or just left out to require GFI in those areas even if more than 6 feet from water. Different areas of the country are way behind on code cycles. When they finally update it might jump up two cycles.

[Alex Zeller]

Sorry I got distracted. What I was trying to say was using multiple lower rated receptacles on a circuit isn't allowed by code. You are allowed to do it on a 20 amp 120v circuit but not allowed to use any receptacle less than what the circuit is rated for. You can have multiple if they are all rated the same.

[Frank Pratt]

Sorry I got distracted. What I was trying to say was using multiple lower rated receptacles on a circuit isn't allowed by code. You are allowed to do it on a 20 amp 120v circuit but not allowed to use any receptacle less than what the circuit is rated for. You can have multiple if they are all rated the same.

That's much better, thanks.

[Michael W. Clark]

I'm not an electrician, but thinking through this, I would not not want a circuit where I have a 20A breaker, 15A circuit wire (14GA?), and multiple outlets. In this scenario, I could plug in (2) 10A loads, and exceed the wire capacity without tripping the breaker. This would be an "unfortunate" situation with wire buried in the wall.

IMO, for a shop, make it all surface mount as needs will change as you add/subtract equipment.

[Jim Becker]

Michael, there's more risk of what you describe with 120v circuits than with 240v circuits in most single woodworker shops. As long as the DC and compressor are on dedicated circuits separate from other machines, it's unlikely that someone is going to run two 240v tools simultaneously simply because their arms are not long enough or they don't have enough of them.

I agree relative to surface mount, particularly for 240v circuits and wish I would have done that initially in my shop Moving things around was more complicated because of that. Anything I've added in the last x number of years has been surface mounted, such as my CNC machine, for that reason. Faster installation and faster/easier changes.

[Mike Henderson]

I'm not an electrician, but thinking through this, I would not not want a circuit where I have a 20A breaker, 15A circuit wire (14GA?), and multiple outlets. In this scenario, I could plug in (2) 10A loads, and exceed the wire capacity without tripping the breaker. This would be an "unfortunate" situation with wire buried in the wall.

IMO, for a shop, make it all surface mount as needs will change as you add/subtract equipment.

I don't know about others but I used 12 gauge wire when I wired up my 120V outlets.

In any case, my understanding is that the wire should match the breaker. So if you put in 20 amp breakers you should use 12 gauge wire.

Mike

[Paul F Franklin]

I'm not an electrician, but thinking through this, I would not not want a circuit where I have a 20A breaker, 15A circuit wire (14GA?), and multiple outlets. In this scenario, I could plug in (2) 10A loads, and exceed the wire capacity without tripping the breaker. This would be an "unfortunate" situation with wire buried in the wall.

IMO, for a shop, make it all surface mount as needs will change as you add/subtract equipment.

You are not allowed to have 14 ga (15 amp) wire with a 20 amp breaker, that's not what an earlier post said. What you are allowed to have are multiple 15 amp receptacles on a 20 amp circuit. The circuit must be wired with 12 ga wire; only the receptacle device is allowed to be 15 amp rated. There is no danger of overload in that situation because a single load that draws more than 15 amps must have a 20 amp plug that won't plug into a 15 amp receptacle. So the receptacle is not overloaded. And multiple smaller loads connected to different 15 receptacles that together draw more than 20 amps will trip the breaker. So the wire is never overloaded. There is nothing to prevent you from using only 20 amp receptacles on a 20 amp circuit (they will accept standard plugs as well as 20 amp plugs), but the code recognizes that most household loads are far less than 15 amps and allow the 15 amp receptacles (which are a little less expensive).