Steam generator wire size

I have a steam generator to connect and I’m wondering about the wire and breaker.
In the installation instructions it says:

Voltage:  240
Phase: 1
Watt: 6,000
AMP Nominal: 25.0
Recommend prodective device: 35
Recommend wire: 8-2 W/G

Do I really need an 8/2 cable or would a 10/2 be conform? It also says that the breaker should be 35 amp, which I can’t find at my supplier. Can I use 30 amp in this case?



Is this inspection related?

To start with you have a 25 amp device that is a resistance load.

Next your talking about changing breaker sizes so the wire size would be based upon the breaker size.

Next the wire size depends upon the wire type.

I suppose you’re going to install this yourself based upon your vast knowledge displayed in this question?

What is the real question?

My question is, can you read directions?
I believe the manufacturer knows what the appliance requires, don’t you?

Well, someone will install it but I will buy the stuff first. My question:

Can I use a 8/2 wire with a 40 amp breaker in this case?

A 6K generator is capable of producing 25 amps at 240V.

Installing a 40 amp breaker will allow something to melt down in the generator before the breaker is tripped.

I would get a 25 amp breaker and size the wire to the breaker.

8/2 on a 40amp will work. However, keep in mind OCPDs are meant to protect the wiring and in turn the structure rather than the appliance. But something is fishy in that while this is a restive load the OP is treating it like a motor load.

A 35 amp breaker is a standard size.

That seems to be not the case up here in Quebec.

I finally asked the manufacturer and they confirmed that a 35 amp or a 40 amp breaker is fine for this unit.

Thanks for all answers.


While I really do like to refrain from answering DIY question on this type of forum as it increases liability to the forum, I will address some of your core questions.

  1. it recommends that the OCPD be 35 amps, this could be a fuse or a circuit breaker. I believe it was Mr. Port whom stated that a 35A circuit breaker is a standard breaker and he is 100% correct. If your supply house seems to lack those sizes i would look elsewhere and follow the manufacturers directives and recommendations.

  2. The manufacturer recommends 8/2 W/G as the conductor choice, I would go with what the manufacturer states and not sure why you would go otherwise?..Cost?..honestly thats not an issue at best.

  3. The manufacturer states 25 AMPS but we also do not know and I wont assume if this may be a continuous load which runs for more than 3 hours at a given time. maybe they are assuming this when recommending the conductor sizes…25* 125% = 31.25A

At the end of the day…you can’t go wrong with following the manufacturers recommendations as you never fully know all the considerations that they have taken advantage of in that recommendation.

Just my thoughts on it…

Lastly…fundamentally the answer to the " can you use a 30A OCPD instead of a 35 A OCPD is yes as it would still protect the conductors…if the 30A does not hold then you would have to go to the 35A OCPD as recommended. Maybe they have already figured that in which is the basis of their recommendation? who knows at this point…

NEC has sections on steam vessels. Also the 80% rule is more for OCPDs rather than conductors.

Do you have a code specific code section? My search turned up no results.

Looking at it again nothing specific to the OP, but in the 2014 NEC:

Section VII, 424.70 and onward.

I did take a peek at that initially but according to the scope in 424.1 I’m not so sure if that article is applicable to the OP.

That’s what Im seeing too. I thought it might be of use at first but seeing the rules apply less to the OP’s boiler.

Incorrect…(in the assumption that I was applying 80% to anything other than to speculate on what the manufacturer may be applying…edited for clarity…lol)

Their is not specific code section on “Steam Generator” and my statement has absolutely nothing to do with the reciprocal of 125% ( which is 80%), it was a statement that possibly the manufacturer figured the load as a continuous load and adjusted accordingly in their recommendation possibly also in accordance with 422.10(A). At this point thats all you have to go on.

It would more align itself within Art 422 than it would Art 424, more along the lines of Sec. 422.13 if I had to stab at it but have no clue of the size.

However…at the end of the day…you can’t even apply Section 424.70 if I wanted too since we are referencing a “Steam” generator (which is probably just a fancy term for boiler…or not…lol) but it’s not a Resistance-Type Boiler so poop on that thought…

So in my mind…lack of info, treat like an appliance and apply Art 422 where applicable as it is just used to generate steam in a shower…or as simply a load that requires a branch circuit and just meets the specs given and CASH the check and move on.

OR…maybe it is simply a “STEAM” generator…lol…that generates steam…lol…which I am pretty sure it is…lol…which I would say just follow the manufacturers instructions and no need to get into speculation.

On a different note…I had one of these in my old home and I hated it…dang thing always game me fits and would barely work one minute and then over steam the next. I ended up removing it and expanding the bathroom area that was sectioned off as a steam area.

Was not worth the trouble…