20 amp outlets off a 30 amp circuit

[skon1212]

I have a question about running 4 20 amp outlets off a 30 amp circuit. I installed a 30 amp outlet for my air compressor last year and I was wondering if I can run 4 20 amp outlets off that same circuit or would I need to do a completely separate run with a 20 amp breaker? The compressor circuit runs from the panel to a disconnect box then to the outlet for the compressor and I wanted to see if I could tap into the compressor line before the switch and run wires for the new outlets. The outlets would basically be for charging cordless tool batteries and small power tools and I would probably not run the compressor at the same time as the outlets. The only other thing I may run off the outlets is a Lincoln 130 welder. Is this just a dumb idea or is it possible?
Thanks

 

[American Locomotive]

That is against code and a safety hazard. 20 amp outlets can only be used on 20 amp (or smaller) circuits.

 

[wyliesdiesels]

I have a question about running 4 20 amp outlets off a 30 amp circuit. I installed a 30 amp outlet for my air compressor last year and I was wondering if I can run 4 20 amp outlets off that same circuit or would I need to do a completely separate run with a 20 amp breaker? The compressor circuit runs from the panel to a disconnect box then to the outlet for the compressor and I wanted to see if I could tap into the compressor line before the switch and run wires for the new outlets. The outlets would basically be for charging cordless tool batteries and small power tools and I would probably not run the compressor at the same time as the outlets. The only other thing I may run off the outlets is a Lincoln 130 welder. Is this just a dumb idea or is it possible?
Thanks

Number of issues with that.

First Im assuming this 30a circuit is 240v for the compressor.

If thats the case, u most likely dont have a neutral for the 120v outlets u want.

Second, since the circuit is 30a, u cant put 20a outlets on that circuit.

U would need a breaker panel to fo what u want to do.

Just run a dedicated circuit for the 20a 120v outlets.

BTW what is the HP rating on the compressor?

That is against code and a safety hazard. 20 amp outlets can only be used on 20 amp (or smaller) circuits.

Actually, 20a outlets are not allowed on 15a circuits the readon being that the circuit could be overloaded...

 

[American Locomotive]

Actually, 20a outlets are not allowed on 15a circuits the readon being that the circuit could be overloaded...

How could a 15 amp circuit be overloaded? There would be a 15 amp breaker protecting the branch.

 

[sberry]

It really doesn't protect it from overload, it protects from people overloading it. A 20 simply allows it and the plug prevents it from being plugged to a circuit where it's not wanted.
Mostly to keep the floor equipment from being plugged in to the general circuits.

 

[yeldogt]

How could a 15 amp circuit be overloaded? There would be a 15 amp breaker protecting the branch.

I was always told the outlet has to mach the fusing device -- with adequate wire.

 

[pattenp]

15A circuit is to have an outlet not over 15A. NEC 210.21(b)(3)

Edit: Need to add NEC 210.21(b)(3) applies to multiple outlets​ on a circuit, not a single outlet on a dedicated circuit.

 

[sberry]

This is a spot the intent of the code should be dug deeper in to. A good example is a lab. Lots of stuff may be on generals, stores the same way. They want to dictate where the cleaning equipment can be plugged in, not on the same circuit as the computers or fish tanks etc.
It doesn't even mean the piece has to have a super current draw but that it is to be restricted, I see a vacuum with 14 cord and 20A end. I saw a smaller one had a 20 end the other day and someone had twisted the prong to fit 15

 

[yeldogt]

This is a spot the intent of the code should be dug deeper in to. A good example is a lab. Lots of stuff may be on generals, stores the same way. They want to dictate where the cleaning equipment can be plugged in, not on the same circuit as the computers or fish tanks etc.
It doesn't even mean the piece has to have a super current draw but that it is to be restricted, I see a vacuum with 14 cord and 20A end. I saw a smaller one had a 20 end the other day and someone had twisted the prong to fit 15

We used to have them at our factory --- and our NYC offices. 20 amp plugs on items not normally thought of as 20amp. The reason -- did not want anyone plugging them into a typical circuit -- or plugging two into the same. It forced the user to use the correct circuit. The item was also normally internally fused.

The reverse is true -- People are always saying that the breaker is only to protect the wire (not correct) .. so they put a 30amp 220v plug on a tool that says to have a 20 amp circuit/ plug.

 

[tyme2par4]

I was always told the outlet has to mach the fusing device -- with adequate wire.

The exception is that you can put multiple 15A outlets on a 20A circuit, as long as the wire is sized properly.

 

[skon1212]

Thank you for the replies and now that I researched a little more you are all correct. I do have a 30 amp dual pole breaker so there is no way it would work. I was just trying to see if I could save some space on my panel. I can still run a new line through my shut off box since it sits on the garage side of my main panel so it is a fairly short run. To run this circuit of 20 amp outlets I should use 12/2 wire correct or should I just use individual 3 individual 12 gage strands?

 

[yeldogt]

The exception is that you can put multiple 15A outlets on a 20A circuit, as long as the wire is sized properly.

Yes .. because the outlet can internally handle the 20 amps.

This came in first for kitchens and then dinning rooms -- if my memory is correct. I did my early rehabs (80's) with all 12g and 20 amp circuits .....thinking I was doing something that was better/safer. It's actually not ... having 15amp control will cut off problems faster -- and reduces fire risk for plugged in appliances.

 

[Norcal]

20A has been required for kitchens & dining rooms since at least the 50's. The OP can do as proposed, but will be wrong, against code, & unsafe.

 

[PoorOwner]

What about a 20 amp fused receptacle and the wire to the receptacle is sized to handle 30A?

Just for discussion sake I am interested if that is allowed or not.

 

[American Locomotive]

What about a 20 amp fused receptacle and the wire to the receptacle is sized to handle 30A?

Just for discussion sake I am interested if that is allowed or not.

That depends on whether or not the terminals on the device attached to the circuit are rated to handle the larger wire.

 

[yeldogt]

What about a 20 amp fused receptacle and the wire to the receptacle is sized to handle 30A?

Just for discussion sake I am interested if that is allowed or not.

That's the safe workaround and how it's done in much of the world -- remember all the fused Christmas lights.

This is how you do small bench motors

Edit -- it will not let me upload a clipping of the supplemental circuit protection description

 

[sberry]

Yes, Christmas lights, power strips. If you added a breaker to that circuit it would be legal. Originally Posted by PoorOwner

What about a 20 amp fused receptacle and the wire to the receptacle is sized to handle 30A?

In some sense the 20A wire could be hooked to 30 and the recept fused at 20. Again, this is a power strip, a 15 plug, 14 wire with 15A fuse to protect wire from overload due to multiple recepts. In reality the strip could be plugged in to a 30A circuit.

 

[tyme2par4]

That depends on whether or not the terminals on the device attached to the circuit are rated to handle the larger wire.

I think you'd be hard pressed to find a 20A outlet that wouldn't accept 10AWG wire. Most devices are designed to accommodate larger wire in case you need to upsize to decrease voltage drop.

 

[checkthisout]

What about a 20 amp fused receptacle and the wire to the receptacle is sized to handle 30A?

Just for discussion sake I am interested if that is allowed or not.

Yes, you can always run larger wire between your panel and plugs so long as the breaker is sized to the receptacle.

 

[sberry]

It could force the tool to be on a 20A circuit. We can see the overcurrent protection at work in a 12 extension cord, has a 15 plug and multiple outlets on the other, really 20A feed thru. You can add 3 way thru a 15A connection. All the 15A hardware will pass 20A thru.

 

[PoorOwner]

Yes, you can always run larger wire between your panel and plugs so long as the breaker is sized to the receptacle.

In the OPs intent it is not doing this though. If the 20amp stuff have a short and the breaker will not trip until 30 amps has passed through the 20 amp stuff. So potentially overheating. Anyone know the correct section of code for this violation?

 

[wyliesdiesels]

In the OPs intent it is not doing this though. If the 20amp stuff have a short and the breaker will not trip until 30 amps has passed through the 20 amp stuff. So potentially overheating. Anyone know the correct section of code for this violation?

When a line to line or line to ground short occurs there is several hundred or thousand amps that flow for split seconds depending on the available short circuit/fault current from the transformer...

What you describe is an overcurrent event- when more current than the device is rated for, travels throgh the device...

2 entirely different things...

In the OPs case, he could have an overcurrent event without tripping a breaker which in turn could cause the 20a outlets to carry above 20a for extended periods of time causing them to get hot and melt...the same can be said of the wire.

An overcurrent event is more dangerous in terms of fire with an oversized breaker vs. a short circuit event where a properly functioning breaker would clear the fault...

 

[AntonLargiader]

To add to what Wylie wrote, breakers have different mechanisms for reacting to overcurrent and to shorting. Overcurrent is a thermal event with a bimetallic strip (which takes time), and shorting trips the breaker instantly via an electromagnetic coil.

 

[sberry]

With over draw or over current not much a problem due to the fact most of it is brought thru a 15 end. A combination of items could overload a wire but more importantly is that the stuff plugged in to this circuit is not rated for connection to circuits larger than 20A. A 16 cord is limited to 20.

 

[sberry]

There are a few things 120v would be safe to connect to 30, some saws, small welders, all come 14 or better cord.