Dryers, Dryers, Dryers...

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hillbilly said:
I disagree.

210.23 states "In no case shall the load exceed the branch circuit amperage rating".

If I'm using one 30A circuit to feed (2) 5000 watt clothes dryers, then ...IMO... I've violated this rule.

I don't read anything in 210.23 that would allow this.
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I'd say that, reading Art. 210.21, Table 210.21(B)(2), and Art. 210.23(B), it is permissable.
 
Have you done a service load calculation to determine if the service is adequate for the load of the additional dryer? If it is, then set a small sub-panel to provide the needed circuit. The cost would be minimal. If they can afford two dryers, and the electricity to run them, they can afford a sub-panel in order to do the job right. If they refuse, then run, do not walk, to the nearest exit and let someone else fool with this mess.
 
haskindm said:
Have you done a service load calculation to determine if the service is adequate for the load of the additional dryer? If it is, then set a small sub-panel to provide the needed circuit. The cost would be minimal. If they can afford two dryers, and the electricity to run them, they can afford a sub-panel in order to do the job right. If they refuse, then run, do not walk, to the nearest exit and let someone else fool with this mess.
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Logic prevails.
"I want another laundry circuit."
But your panel is full.
"I want it anyway, figure it out."
You need a larger panel, a different panel, or a sub panel, or a service upgrade.
"I don't want to pay for that, I'm on a budget."

IMHO - If you can afford the new laundry pair & plumbing to hook it up in a new location, and the associated wiring, none of the solutions above are beyond your financial reach.

There is a difference between "I cannot afford" and "I do not want to spend."
 
petersonra said:
and it won't because the breaker will trip. :)
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I've always thought that the "branch circuit amperage rating" had something to do with the conductor ampacity.

I'm learning something new every day.

steve
 
LarryFine said:
I'd say that, reading Art. 210.21, Table 210.21(B)(2), and Art. 210.23(B), it is permissable.
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I guess that this is where we agree to disagree.

I've read and re-read the applicable articles and I just can't believe that the intent of the code is to allow the connection of (seperate) fixed loads to a 30 amp branch circuit that (in combination) exceed the circuit ampacity.

210.24 refers us to Table 210.24 which clearly states that the maximum load on a 30A branch circuit is 30 Amps.
The load of (2) 5000 watt clothes dryers (240V) is 41.7 amps.

If I fix two seperate loads to a circuit, sooner or later, both of those loads will be turned on at the same time.
At that point.. IMO..., A violation of 210.23 has occured.

The cause of confusion (in my mind) is the difference between fixed loads verses receptacle outlets.

I know that I can place as many receptacles outlets on a circuit as I want (residential), but saying that I can place as many fixed loads as I want on a circuit, even if they exceed the circuit ampacity, just doesn't agree with what I've always (thought that I've) known about the rules concerning circuit loading.

Is the concensus here that it's allowed to add as many fixed loads as I want to a 30A circuit, as long as the largest of the loads doesn't exceed 80% of the circuit ampacity?
Can I add 3, 4, 5...etc... 24 amp (max) fixed loads to a single 30A branch circuit?
If this is true, I've really learned something today.

steve
 
hillbilly said:
I guess that this is where we agree to disagree.

The cause of confusion (in my mind) is the difference between fixed loads verses receptacle outlets.
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I agree with you that this is the crux of the issue. :smile:

Where might I find how "fixed loads" are treated differently than receptacle loads?

Is the concensus here that it's allowed to add as many fixed loads as I want to a 30A circuit, as long as the largest of the loads doesn't exceed 80% of the circuit ampacity?
Can I add 3, 4, 5...etc... 24 amp (max) fixed loads to a single 30A branch circuit?
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Again, does the presence of receptacles make a difference? Let's play:

Starting with 210.21(B), we jump to (2) because we want to use two receptacles, so we look at (2) and (3), with which two 30a receptacles comply. Half of your 41.7 example is 20.85a, less than 24a.

210.23 doesn't affect us, so let's look at 210.24, especially its Table. I obviously agree with you that it says what it says. :smile: But, here's the philosophical twist: As the electrician, it doesn't apply to us, since we don't plug the applainces in.

How can the limitations of the third column of Table 210.24 (effectively banning two dryers) be any more enforced than enforcing the limitations of the first two columns?

210.19(A)(1) starts by saying "Branch-circuit conductors shall have an ampacity not less than the maximum load to be served." Okay, the load to be served is a single dryer. Tell the customer that.

How do you stop someone from plugging in a toaster-oven, a counter-top microwave, and a coffee maker into a single SA branch circuit?

Besides, if the conductors are joined together within the panel, the branch circuits will not be overloaded by simultaneous use. If you're worried about the pigtails at the breaker, use #8 for them.

Of course, I'm just playing Devil's Advocate here, but I honestly would have no problem having two dryer receptacles on a single circuit, expecting that most people only use one dryer at a time.
 
wirebender said:
I don't even know anyone that has more than one dryer, unless you count the ones in the junk pile on the back lot.:D
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Not unusual around here... I've seen 2 washers/dryers in the same room, his/hers situation, she got tired of grease and dirt getting on her nice clothes...:grin:
 
I can't believe this is still going. :grin:

Everyone of us has put more then one 20 amp duplex on a 20 amp circuit.

Many times there will be more load plugged into the circuit then the circuit could handle at once. Say the SABC, with a toaster, coffee maker, can opener and radio all plugged into it....that would likely be over 20 amps.

It happens all the time.

But now when the circuit size changes to 30 amps everyone is getting all worried......I don't understand it at all.
 
wirebender said:
I don't even know anyone that has more than one dryer, unless you count the ones in the junk pile on the back lot.:D
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Actually I use the clotheline in our backyard for about half of the year. So you might say I use 1/2 a dryer! Still a 30 amp circuit though :) e/m.
 
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I think this is an area that can use clarification.

For me, I see this initial statement in 210.23: "In no case shall the load exceed the branch-circuit ampere rating."

If we connect two fixed-in-place dryers to the same circuit totalling over 30A, how are we complying with this rule? Sure, 210.23(B) says that any one load can't exceed 80% of the circuit, but how does that negate the primary requirement that we not overload any circuit?

We're not talking about general purpose receptacles, we're talking about big appliances that don't move. Granted, it's not screwed to the floor, but is that really relevant?
 
I'm with George. So there's supposedly no limit to the number of receptacles on the laundry circuit? Does this mean a 50a range receptacle can be on the same circuit as a 50a welder receptacle in the garage?
 
georgestolz said:
If we connect two fixed-in-place dryers to the same circuit totalling over 30A, how are we complying with this rule? Sure, 210.23(B) says that any one load can't exceed 80% of the circuit, but how does that negate the primary requirement that we not overload any circuit?
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Okay, there's that "fixed in place" term again. I don't see it defined in Art 100, so what is it? "Fixed" sounds like "hard-wired" to me. Are dryers "fixed" or merely stationary?
 
If I had 3 - 15 amp motors to wire at a factory. Each was 120 volts. I decided to hard wire them. You are then saying I would have to have 3 circuits run to these motors. Now I decide to use a cord and plug. I can use one circuit to wire all 3 motors??????

Doesn't sound right to me.
 
Dennis Alwon said:
If I had 3 - 15 amp motors to wire at a factory. Each was 120 volts. I decided to hard wire them. You are then saying I would have to have 3 circuits run to these motors. Now I decide to use a cord and plug. I can use one circuit to wire all 3 motors??????

Doesn't sound right to me.
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90.1(B)..........
 
iwire said:
I can't believe this is still going. :grin:

Everyone of us has put more then one 20 amp duplex on a 20 amp circuit.

Many times there will be more load plugged into the circuit then the circuit could handle at once. Say the SABC, with a toaster, coffee maker, can opener and radio all plugged into it....that would likely be over 20 amps.

It happens all the time.

But now when the circuit size changes to 30 amps everyone is getting all worried......I don't understand it at all.
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I'm not trying to start a argument.
I'm just trying to understand.:smile:

Lets change the circuit size to 20 amps.

Say that I mount two (120V) 1800 watt microwave ovens side by side.

Both are built in and connected by cord and plug.
There are 2 receptacles in the cabinet above, both fed by the same 20A branch circuit.

Can I (by code) use this circuit to power both microwaves?

I say no.

I have intentionally and permanently connected two appliances to the same circuit while knowing that both can't be operated at the same time without overloading the circuit.

In my opinion, I have violated 210.23



Another example

A homeowner places two 1800 watt microwave ovens on the counter top and plugs them both into the same SABC.

Is this OK?
As far as I'm concerned (code wise), it's none of my business.

If my SABC is properly installed and protected, that is all that I can do.
What the homeowner does with the general use receptacles after I leave is out of my control....it's his responsibility to manage the loads in order to not overload the circuit.

In my opinion, the heart of the matter rests with the fact that I have installed a circuit in which the homeowner has no control over whether it's overloaded or not.......other than remembering not to operate both microwaves at the same time.

Explain that when the homeowner calls because the breaker is tripping.
"Well sir (or ms.) I forgot to tell you that you can't use both ovens at the same time".

"What? Why the heck would I buy two if I couldn't operate them at the same time"?

...Verses...

(Homeowner) "The breaker for my kitchen counter receptacles keeps tripping, I'd like for you to check it out".

(Me after inspection) "Sir, you've overloaded the circuit by plugging two 15 amp microwaves into a single 20 amp circuit".

(Homeowner) "That makes sense, I'll move it onto another circuit".

(Me) "Glad I could help, that'll be $75".

steve
 
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