Two Steamists on 100amp subpanel. One popping breaker.

[JohnDS]

Ok,

Customer has a 100amp sub panel installed in the attic of bathroom. This subpanel is powering the bath lighting and receptacle outlets and two steamists. Each steamist has #6 romex run to it and each on a 60amp breaker. One of the steamists is tripping its breaker and it is clear why according to specs. Whats weird is that customer says both been working fine for 3 or 4 months. Actually I am surprised the sub panel main breaker is not tripping. Here are the specs.

My questions are:

1) Why does the manufacturer have such an upsized breaker on the Tsg-15? It says 63amps and 80amp breaker?

2) I am pretty sure the tsg-15's #6 is not correct for an 80amp breaker, so would #4 be ok?



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[JFletcher]

Ok,

Customer has a 100amp sub panel installed in the attic of bathroom. This subpanel is powering the bath lighting and receptacle outlets and two steamists. Each steamist has #6 romex run to it and each on a 60amp breaker. One of the steamists is tripping its breaker and it is clear why according to specs. Whats weird is that customer says both been working fine for 3 or 4 months. Actually I am surprised the sub panel main breaker is not tripping. Here are the specs.

My questions are:

1) Why does the manufacturer have such an upsized breaker on the Tsg-15? It says 63amps and 80amp breaker?

2) I am pretty sure the tsg-15's #6 is not correct for an 80amp breaker, so would #4 be ok?

View attachment 14828

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I'm guessing continuous load, so 80A x 80% = 64A. Seems okay to me.

 

[JohnDS]

I'm guessing continuous load, so 80A x 80% = 64A. Seems okay to me.

Oh lol. I should have thought of continuous load.
Were you at all referring to question number two when you said, "seems ok to me"?

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[JFletcher]

Oh lol. I should have thought of continuous load.
Were you at all referring to question number two when you said, "seems ok to me"?

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No, just the recommended OCPDs for the ampacities listed. I dont have a code book in front of me so no definitive answer for the wire sizes, tho I believe #4 is good for 70A even with 60*C NM, ambient temps and short distances for VD not factored.

eta: if the wire is going thru the attic, ambient temps may be coming into play now; it's been markedly warmer last few weeks. An attic that was running 90*F max the past few months may be seeing 120*+ now.

 

[Cow]

Whats weird is that customer says both been working fine for 3 or 4 months. Actually I am surprised the sub panel main breaker is not tripping. Here are the specs.

I take it you weren't the original electrical contractor that wired these?

If it's only been 3 or 4 months since installation, this should be covered under warranty. I wouldn't touch anything, I would have the customer call the original electrical contractor back out to take care of this issue.

 

[JFletcher]

Agree with Cow. Also, I found the install instructions on-line:

http://steamist.com/wp-content/uploads/2015/02/201-G-1.pdf

Note this:

"CAUTION: Steam generators must NOT be installed outdoors, in moist, humid areas, in areas prone to freezing, or extreme heat such as an unventilated attic. To do so will void the warranty"

Are the units in the attic?

 

[GoldDigger]

No, just the recommended OCPDs for the ampacities listed. I dont have a code book in front of me so no definitive answer for the wire sizes, tho I believe #4 is good for 70A even with 60*C NM, ambient temps and short distances for VD not factored.

eta: if the wire is going thru the attic, ambient temps may be coming into play now; it's been markedly warmer last few weeks. An attic that was running 90*F max the past few months may be seeing 120*+ now.

Having wiring in the attic will not have any effect on the breaker. But if the breakers themselves are in a high ambient temperature they will trip at a significantly lower current than at normal temperatures.
They were too small to start with, and the high temperature just made it worse.

 

[JFletcher]

Having wiring in the attic will not have any effect on the breaker. But if the breakers themselves are in a high ambient temperature they will trip at a significantly lower current than at normal temperatures.
They were too small to start with, and the high temperature just made it worse.

Yeah John wrote in his first post:

"Customer has a 100amp sub panel installed in the attic of bathroom."

I took that to mean the attic above the bathroom; I'm sure he'll clarify that as well as where the steamist units are installed.

 

[topgone]

If that's the case, that's the reason why the HO hired another tech to fix the thing.

 

[JohnDS]

Yes steamists are in the bathroom attic as well.

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[kwired]

If you have the 63 amp unit and they are continuous load (I would assume they are, never seen or heard of a steamist) then minumum conductor ampacity is 63 x 1.25 = 78.75. Minimum overcurrent device would be 80 amps also.

6 AWG is acceptable if the units are not a continuous load and using 75C conductors but 60 amp breaker is still too little.

You mentioned these are fed with NM cable - NM must be selected using 60C ampacity and 6 AWG is only good for 55 amps. It could be protected by a 60 amp breaker but load still must be under 55.

 

[JFletcher]

If you have the 63 amp unit and they are continuous load (I would assume they are, never seen or heard of a steamist) then minumum conductor ampacity is 63 x 1.25 = 78.75. Minimum overcurrent device would be 80 amps also.

6 AWG is acceptable if the units are not a continuous load and using 75C conductors but 60 amp breaker is still too little.

You mentioned these are fed with NM cable - NM must be selected using 60C ampacity and 6 AWG is only good for 55 amps. It could be protected by a 60 amp breaker but load still must be under 55.

Sounds like he has the tsg 15 model but it's wired for a 12. Sub panel is in the attic as well, which could easily have seen 50*C ambient already, if not 60*C or more.

I surmise the unit has been functioning okay the past months because it's been fairly cool. If so, the problems are just going to worsen over the summer months. Breakers (and wire) will carry more than their rated load in colder conditions.

Also going to take a wag that the sub panel main isnt tripping because both units have not run simultaneously.

 

[iwire]

There is no way I would call a steam generator a continuos load.

 

[kwired]

There is no way I would call a steam generator a continuos load.

I know nothing about them, and is why I mentioned both continuous and non continuous in my reply.

Are these steam generators like what may be used for a sauna? Why would you want such a thing in a bathroom? Usually we are wanting to remove humidity from a bathroom but this would be adding humididy:huh:

Only steam generator I am familiar with is industrial steam boilers

 

[GoldDigger]

A sauna is technically dry heat except when you toss water on the stones. A steam generator (mist generator) is often used in a large shower stall with waterproof surfaces all around.
You would have to ventilate the steam that gets into the rest of the bathroom.

 

[kwired]

A sauna is technically dry heat except when you toss water on the stones. A steam generator (mist generator) is often used in a large shower stall with waterproof surfaces all around.
You would have to ventilate the steam that gets into the rest of the bathroom.

Why is it needed? Sounds to me if they want to waste some money on energy they can just send it to me and I will get rid of their money for them

Or is there some therapeutic reasoning for doing this?

If I want water vapor I turn the water in the shower to a hotter temp, if I want "steam" I go to one of my industrial customers that has real steam boiler:happyyes:

 

[topgone]

Why is it needed? Sounds to me if they want to waste some money on energy they can just send it to me and I will get rid of their money for them

Or is there some therapeutic reasoning for doing this?

If I want water vapor I turn the water in the shower to a hotter temp, if I want "steam" I go to one of my industrial customers that has real steam boiler:happyyes:

In an ideal world, you can do that. But people make do with what is available, locally. That said, the HO will just have to get the right tech and solve his/her problem.

 

[JohnDS]

Thanks guys for all the replies. I have been a little busy with work. Ok, so how can I make this TSG-15 work. I am going to give the 80amp breaker a shot but obviously I have to change out the wire. What size awg would be suitable given the circumstances?

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[kwired]

Thanks guys for all the replies. I have been a little busy with work. Ok, so how can I make this TSG-15 work. I am going to give the 80amp breaker a shot but obviously I have to change out the wire. What size awg would be suitable given the circumstances?

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If staying with NM cable you have to use 60C ampacity table. Then it comes down to whether or not this is continuous load or not.

If it is not a continuous load a 70 amp breaker should be good enough other then maybe the instructions say 80 and 4 AWG conductor.

If it is continuous load and you are using NM cable it will need to be at least 3 AWG, and the 80 amp breaker would be required even without instructions calling for 80. If it is continuous but able to use 75C conductor it still can be 4 AWG.

 

[JFletcher]

Thanks guys for all the replies. I have been a little busy with work. Ok, so how can I make this TSG-15 work. I am going to give the 80amp breaker a shot but obviously I have to change out the wire. What size awg would be suitable given the circumstances?

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I agree with kwired, tho you still have some potential problems with the sub panel and steamist units being located in the attic: mainly, warranty issues if its not ventilated (tho that's on the HO and original EC), and that 80A breaker may not be enough in the dead of summer with ambient temps going to 140*+ in the avg attic. At 60*C, an 80A breaker will carry ~60-65A. I'd like to think the original EC took into account ambient temps, but maybe not...

Are the two units interlocked in any way or configured to run one at a time? What size is the feeder to the subpanel? You can pretty much guess if one unit is popping a 60A breaker already that two will trip a 100A. Two 80A breakers/63A loads on a 100A subpanel (plus the lighting/receptacles you mentioned in post #1) doesnt sound workable to me.