- Location
- Massachusetts
Yes it has to run with the conductors but the same EGC can be used for multiple outlets.
electrickangaroo had said the EGC could not be used for more than one outlet.
Clothes Dryer Circuit
- Thread starter donf
- Start date
- Status
Yes it has to run with the conductors but the same EGC can be used for multiple outlets.
electrickangaroo had said the EGC could not be used for more than one outlet.
donf
Member
- Location
- Tidewater Virginia
Multiple 30 amp receptacles.
Multiple 30 amp receptacles.
The following question has been sent to the NEC for clarification, the answer should be received within 5 working days:
"Greetings,
I need clarification on two sections of Article 210.23, please.
I have a customer that would like me to extend the Dryer BC (30 amp) across the garage to another 30 amp receptacle that will service a welding machine.
My position is that article 210.23 is the governing article. This article states that I cannot have a connected load greater than the BC rating. In this situation, two 30 amp pieces of equipment would equal a 60 amp load if both devices were in use at the same time.
The GC responded that 210.23(B) allows for multiple receptacles as long as no single load was greater than 24 amps.
My response is that 210.23 supersedes 210.23(B) and that 210.23(B) is actually limiting the maximum allowable load of multiple receptacles connected devices to 24 amps. Not one device that is 24 amps and one device that is 6 amps.
As I interpret 210.23, it is telling me that I can have up to 30 amps on a 30 amp circuit.
210.23(B) is telling me that I can have as many 30 amp receptacles as I want, but that I cannot have a connected load greater that 24 amps.
For example: according to 210.23(B), I can have one load at 18 amp and one load at 6 amp. What I cannot have is one load at 22 amp and one load at 8 amp.
Am I miss interpreting this article of code?"
Multiple 30 amp receptacles.
The following question has been sent to the NEC for clarification, the answer should be received within 5 working days:
"Greetings,
I need clarification on two sections of Article 210.23, please.
I have a customer that would like me to extend the Dryer BC (30 amp) across the garage to another 30 amp receptacle that will service a welding machine.
My position is that article 210.23 is the governing article. This article states that I cannot have a connected load greater than the BC rating. In this situation, two 30 amp pieces of equipment would equal a 60 amp load if both devices were in use at the same time.
The GC responded that 210.23(B) allows for multiple receptacles as long as no single load was greater than 24 amps.
My response is that 210.23 supersedes 210.23(B) and that 210.23(B) is actually limiting the maximum allowable load of multiple receptacles connected devices to 24 amps. Not one device that is 24 amps and one device that is 6 amps.
As I interpret 210.23, it is telling me that I can have up to 30 amps on a 30 amp circuit.
210.23(B) is telling me that I can have as many 30 amp receptacles as I want, but that I cannot have a connected load greater that 24 amps.
For example: according to 210.23(B), I can have one load at 18 amp and one load at 6 amp. What I cannot have is one load at 22 amp and one load at 8 amp.
Am I miss interpreting this article of code?"
dana1028
Senior Member
- Location
- San Francisco Bay area
I completely agree with Iwire on this one.
210.23 'In no case shall the load exceed the branch-circuit ampere rating." As Iwire has said, something plugged in does not constitute a load. If you have an electric dryer operating and the welder not operating you have not exceeded the BC rating.
210.23(B) - 30A Branch Circuits. "A 30A BC shall be permitted to supply...utilization equipment in any occupancy. A rating of any one cord-and-plug connected utilization equipment shall not exceed 80% of the BC ampere rating."
This clearly permits multiple pieces of equipment to be cord-and-plug connected to a single 30A rated branch circuit.
If neither the elect. dryer or the welder exceed the 80% for 'any one C&P connected equipment' we're good to go.
210.23 'In no case shall the load exceed the branch-circuit ampere rating." As Iwire has said, something plugged in does not constitute a load. If you have an electric dryer operating and the welder not operating you have not exceeded the BC rating.
210.23(B) - 30A Branch Circuits. "A 30A BC shall be permitted to supply...utilization equipment in any occupancy. A rating of any one cord-and-plug connected utilization equipment shall not exceed 80% of the BC ampere rating."
This clearly permits multiple pieces of equipment to be cord-and-plug connected to a single 30A rated branch circuit.
If neither the elect. dryer or the welder exceed the 80% for 'any one C&P connected equipment' we're good to go.
donf
Member
- Location
- Tidewater Virginia
Except when:
Except when:
Except when the dryer (upstairs in laundry room) is in operation and he/she decides on welding (garage) together a steel sculpture.
Why won't it work, they are both plugged in and ready for use?
I'm sorry, but I have to disagree with you. If I am incorrect, so be it. We will all know together. Also, at the risk of being redundant, we all know that the NEC is the minimum safety level.
To me, common sense says do not share the circuit, but I guess I stand-alone
Except when:
Except when the dryer (upstairs in laundry room) is in operation and he/she decides on welding (garage) together a steel sculpture.
Why won't it work, they are both plugged in and ready for use?
I'm sorry, but I have to disagree with you. If I am incorrect, so be it. We will all know together. Also, at the risk of being redundant, we all know that the NEC is the minimum safety level.
To me, common sense says do not share the circuit, but I guess I stand-alone
dana1028
Senior Member
- Location
- San Francisco Bay area
The OP did not ask about common sense or 'proper' design...Nor is the NEC concerned with this.
As an electrical inspector I am not allowed to enforce my concept of 'proper' design during an inspection. The question is whether or not this scenario is code compliant - I believe it to be and have passed such installations in the past.
scenario: fully loaded svc panel [loaded meaning all breaker spaces have been used, no space left in the panel for additional breakers] - homeowner wants this welder outlet.
Option: install an upgrade service with spare breaker spaces or extend the 30A dryer circuit.
The breaker only has to trip once for wife and hubby to coordinate their respective use of equipment.
As an electrical inspector I am not allowed to enforce my concept of 'proper' design during an inspection. The question is whether or not this scenario is code compliant - I believe it to be and have passed such installations in the past.
scenario: fully loaded svc panel [loaded meaning all breaker spaces have been used, no space left in the panel for additional breakers] - homeowner wants this welder outlet.
Option: install an upgrade service with spare breaker spaces or extend the 30A dryer circuit.
The breaker only has to trip once for wife and hubby to coordinate their respective use of equipment.
donf
Member
- Location
- Tidewater Virginia
Proper Design
Proper Design
Dana,
I am the OP.
Personally, I am coming to the viewpoint that I blurred the lines between circuit design and Code.
The fact that you can have multiple recepts on the circuit does not in and of itself say that you have to have them.
Further back there was some discussion regarding one 30 amp circuit serving multiple recepts on a factory floor. The circuit was used to service a welding machine that traveled to where it was needed.
That makes absolute sense to me now when I move it into a design perspective, especially if they are only using one welder on the circuit. If they are using several at one time then the CB would be tripping.
Hopefully, we will get a response back from the NEC, sooner rather than later.
Proper Design
Dana,
I am the OP.
Personally, I am coming to the viewpoint that I blurred the lines between circuit design and Code.
The fact that you can have multiple recepts on the circuit does not in and of itself say that you have to have them.
Further back there was some discussion regarding one 30 amp circuit serving multiple recepts on a factory floor. The circuit was used to service a welding machine that traveled to where it was needed.
That makes absolute sense to me now when I move it into a design perspective, especially if they are only using one welder on the circuit. If they are using several at one time then the CB would be tripping.
Hopefully, we will get a response back from the NEC, sooner rather than later.
readydave8
re member
- Location
- Clarkesville, Georgia
- Occupation
- electrician
or a dpdt relay w/toggle switch so they can't work at same time
or manual transfer switch
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
Lets look at the loads a little more carefully.
240 volts x 30 amps = 7200 VA
Average household clothes dryer is 5000 maybe 5500 VA.
If dryer is 5500 VA that leaves 1700 VA of circuit capacity not being used (neither load is a continuous load).
Once the dryer is up to normal operating temperature the heating element cycles on/off as needed to maintain temperature.
Welder draws more current when selecting a higher amperage for the electrode. High amperages are needed for welding thicker materials.
Depending on how high the welder is set and how hard it is being used one very well may be able to use both welder and dryer at same time without opening the branch circuit overcurrent device. It will allow overloading for short periods which the welding act generally is. If welding for long periods the typical welder you would find at a home is not designed for this kind of duty cycle.
240 volts x 30 amps = 7200 VA
Average household clothes dryer is 5000 maybe 5500 VA.
If dryer is 5500 VA that leaves 1700 VA of circuit capacity not being used (neither load is a continuous load).
Once the dryer is up to normal operating temperature the heating element cycles on/off as needed to maintain temperature.
Welder draws more current when selecting a higher amperage for the electrode. High amperages are needed for welding thicker materials.
Depending on how high the welder is set and how hard it is being used one very well may be able to use both welder and dryer at same time without opening the branch circuit overcurrent device. It will allow overloading for short periods which the welding act generally is. If welding for long periods the typical welder you would find at a home is not designed for this kind of duty cycle.
stew
Senior Member
- Location
- federal way,washington
I disagree kwired. The lincoln A/C 225 home arc welder is a unit that is the most common little home welder around. At a setting of 130 amps which is what you generally run 1/8 electrode on with a weld using the duty cycle of the welder I can gaurantee that a dryer circuit wont hold. The duty cycle of this little machine is 20% which means that you can weld for 2 minutes out of 10 before you need to let the mahine cool to prevent winding damage. I have seen 30 amp breakers trip after a very short time running 1/8 electrode for any lengthy period.
- Location
- Massachusetts
I find a lot of that odd as I have run my own 225 amp welder on a 30 amp circuit often.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
I run one on 30 amp circuit often myself.
How do you run something a short time for a lengthy period?
stew
Senior Member
- Location
- federal way,washington
I wanst saying it couldnt be done just that tripping will occur if used at or near sevice factor running 1/8 electrode or larger, The 225 linclwelder 225s and the miller thunderbolt both draw 50 amps full load. Of course if you run 3/32 electrode and dont overload the breaker for long periods you wont trip. I always reccomend 60 amp wire and a 50 amp outlet with a 50 amp breaker if I am running a new circuit. Both machines come with a 5 amp cord and surface mount outlet.
donf
Member
- Location
- Tidewater Virginia
And now the response from NEC
And now the response from NEC
1. Section 210.23 applies in all cases and requires that the single utilization equipment load or the combined utilization equipment load not exceed the rating of the branch circuit.
2. Section 210.23(B) limits the load of any one cord-and-plug-connected utilization equipment to 24 amperes where multiple loads are supplied.
3. Section 210.23(B) does not limit the combined cord-and-plug-connected or permanently connected utilization equipment load to 24 amperes. The main requirement of 210.23 covering the total load on the branch circuit is applicable.
4. The circuit sizing and overcurrent protection requirements for electric welders are covered in Article 630.
And now the response from NEC
1. Section 210.23 applies in all cases and requires that the single utilization equipment load or the combined utilization equipment load not exceed the rating of the branch circuit.
2. Section 210.23(B) limits the load of any one cord-and-plug-connected utilization equipment to 24 amperes where multiple loads are supplied.
3. Section 210.23(B) does not limit the combined cord-and-plug-connected or permanently connected utilization equipment load to 24 amperes. The main requirement of 210.23 covering the total load on the branch circuit is applicable.
4. The circuit sizing and overcurrent protection requirements for electric welders are covered in Article 630.
Last edited:
renosteinke
Senior Member
- Location
- NE Arkansas
Where is the definition of 'convenience outlet?' A fair question. I would draw your attention to 210.21(B)(2), where branch circuits supplying two or more receptacles are discussed. I will concede that there is no reference to voltage.
Where does the NEC mention 'rolling around?' First off, my comment was in reply to another poster who described a situation where equipment was moved about in an industrial setting - I did not bring in that element. However, for your amusement, you might look at 210.19(A)(2), where there;s a reference to 'portable loads.'
The dryer + welder dilemma stumbles over the diverse nature of the loads. While we have general rules regarding sizing wire for ampacity, and breakers for overcurrent protection, in both cases the rules are severely modified for for these particular loads.
We 'forget' the nameplate of the dryer, and instal an already oversize 30-A circuit, using #10 wire. (Doing the math, we might be able to use a 25-amp breaker).
For the welder, we look to 630 ... and, by the time we're done, we might very well have a situation where code would allow us to use a 100-A breaker on #12 wires. It all depends on the nameplate of that specific welder- most notably on the 'duty cycle.'
Think about that for a moment. Fow the welder, #10 might be more wire than we must use, but that's a small small waste. Of greater concern is that 30-Amp breaker. That the NEC would allow a 100-Amp breaker for the welder suggests that ordinary welding activities can very easily lead to nuisance tripping of the 30-Amp breaker ... and we sure don't want to put the dryer on a 100-Amp breaker, do we?
Have a more capable welder, with a higher duty cycle, and the breaker sizing issue gets even worse. Remember: in welding a 'short circuit' is a good thing
I just don't see any way to reconcile the two different uses on one circuit. One feeder, yes ... one circuit, no.
Can you do it? Does it work? Is this the reasoning of someone so careful as to call 811 for a ground rod? Seems pretty daring to me.
Where does the NEC mention 'rolling around?' First off, my comment was in reply to another poster who described a situation where equipment was moved about in an industrial setting - I did not bring in that element. However, for your amusement, you might look at 210.19(A)(2), where there;s a reference to 'portable loads.'
The dryer + welder dilemma stumbles over the diverse nature of the loads. While we have general rules regarding sizing wire for ampacity, and breakers for overcurrent protection, in both cases the rules are severely modified for for these particular loads.
We 'forget' the nameplate of the dryer, and instal an already oversize 30-A circuit, using #10 wire. (Doing the math, we might be able to use a 25-amp breaker).
For the welder, we look to 630 ... and, by the time we're done, we might very well have a situation where code would allow us to use a 100-A breaker on #12 wires. It all depends on the nameplate of that specific welder- most notably on the 'duty cycle.'
Think about that for a moment. Fow the welder, #10 might be more wire than we must use, but that's a small small waste. Of greater concern is that 30-Amp breaker. That the NEC would allow a 100-Amp breaker for the welder suggests that ordinary welding activities can very easily lead to nuisance tripping of the 30-Amp breaker ... and we sure don't want to put the dryer on a 100-Amp breaker, do we?
Have a more capable welder, with a higher duty cycle, and the breaker sizing issue gets even worse. Remember: in welding a 'short circuit' is a good thing
I just don't see any way to reconcile the two different uses on one circuit. One feeder, yes ... one circuit, no.
Can you do it? Does it work? Is this the reasoning of someone so careful as to call 811 for a ground rod? Seems pretty daring to me.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
There are light duty welders out there with a 5-15 cord end factory installed on them. If supplied by QO breakers with a good supply you must use the high magnetic breaker otherwise you will have a lot of nuisance tripping. You also can not have much if any additional load on the circuit or you will have tripping problems.
NEC does not adress this unless you are dedicating a receptacle for this welder. People buy this welder to be able to plug it in almost anywhere the plug will fit into the receptacle. If they have tripping problems they plug it in someplace else or learn to manage the load on the circuit better, and in some cases (hopefully no electricians do this) put in a higher setting circuit breaker.
NEC does not adress this unless you are dedicating a receptacle for this welder. People buy this welder to be able to plug it in almost anywhere the plug will fit into the receptacle. If they have tripping problems they plug it in someplace else or learn to manage the load on the circuit better, and in some cases (hopefully no electricians do this) put in a higher setting circuit breaker.
mivey
Senior Member
Then that should not be a problem because after we diversified the loads, we find that these loads will not be on at the same time.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
How can you guarantee that?
- Location
- Massachusetts
We don't have to.
How do you guarantee any multiple receptacle circuit will not be overloaded?
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
I disagree but the post said that the equipment will not be on at the same time. You cannot guarantee that.
donf
Member
- Location
- Tidewater Virginia
Time out, please
Time out, please
From the git-go on this thread, my position has been that the potential is there for both devices to be active at the same time.
eg. Dryer in a laundry room out of sight from welder. Dryer active, and user decides to weld the world's greatest steel statue.
What 210.23 says (by way of the NEC interpretation) is that the governing rule is that you cannot have multiple devices on the circuit that would demand more amperage than the circuit is allowed.
If I have a dryer that is 22 amps and a welder that is 19 amps, that would be allowed by 210.23(B), but prohibited by 210.23 because the demand load (41 amps) exceeds the 30 amp limit of the circuit.
Time out, please
From the git-go on this thread, my position has been that the potential is there for both devices to be active at the same time.
eg. Dryer in a laundry room out of sight from welder. Dryer active, and user decides to weld the world's greatest steel statue.
What 210.23 says (by way of the NEC interpretation) is that the governing rule is that you cannot have multiple devices on the circuit that would demand more amperage than the circuit is allowed.
If I have a dryer that is 22 amps and a welder that is 19 amps, that would be allowed by 210.23(B), but prohibited by 210.23 because the demand load (41 amps) exceeds the 30 amp limit of the circuit.
- Status