# 3600w 208v heater on 20 amp breaker trip or not?



## kolyan2k (Apr 13, 2014)

As the title says. Would hate to run 30amp line over 1.3amps. You think ok for inspection?


----------



## wildleg (Apr 12, 2009)

your post could contain a lot more info.


however, if it is really 3600w on 208 then its a violation and needs to be on a 25


----------



## kolyan2k (Apr 13, 2014)

wildleg said:


> your post could contain a lot more info.
> 
> 
> however, if it is really 3600w on 208 then its a violation and needs to be on a 25


Running MC cable to forced air heaters which are 3600/208. They are in violation by 1.3amp after you overside the circuit by 125%. Next size up is running 10/2 which is a huge pain.


----------



## Southeast Power (Jan 18, 2009)

kolyan2k said:


> Running MC cable to forced air heaters which are 3600/208. They are in violation by 1.3amp after you overside the circuit by 125%. Next size up is running 10/2 which is a huge pain.


Do they have a thermostat?

Are they rated for 208 or 208/240??


----------



## 99cents (Aug 20, 2012)

kolyan2k said:


> As the title says. Would hate to run 30amp line over 1.3amps. You think ok for inspection?


Sure. Just tell the inspector that the guys on ET said it was okay.


----------



## kolyan2k (Apr 13, 2014)

Southeast Power said:


> Do they have a thermostat?
> 
> Are they rated for 208 or 208/240??


Yes they have thermostats but will be placed in pretty cold area so will be running often. They are 208/240 3600/4800 watt. If it was just one, I wouldnt care, but have to install like 7 of them, and thats 7 home runs + need to snake them too 



99cents said:


> Sure. Just tell the inspector that the guys on ET said it was okay.


Well, I am just curious what people in here think. I mean its 1.3 amps.....I am sure some inspectors wouldn't care as well.

I am more curious if a 20AMP breaker loaded with 17.3amp 24/7 would it trip or no?


----------



## MXer774 (Sep 1, 2014)

Alright I want in. 

You never stated if the unit was single or three phase. I see from your calcs it's single. 
Have you even seen the nameplates on these units?
Specs?
What does the MOCP state?


----------



## kolyan2k (Apr 13, 2014)

MXer774 said:


> Alright I want in.
> 
> You never stated if the unit was single or three phase. I see from your calcs it's single.
> Have you even seen the nameplates on these units?
> ...




Yes, single phase. Specs are on website. Doesnt say anything besides 3600 watt 208 volts. Which would need 10/2 30amp according to code. But again, even 0.1amps over would require same 10/2 30amp....

https://www.marleymep.com/products/qmark/commercial-fan-forced-wall-heater-lfk-series

its actually 1.6amps over not 1.3 my mistake


----------



## Southeast Power (Jan 18, 2009)

What makes you think it's a continuous load?
#12 is rock solid rated for 30 amps and has to be fused at 20.
At 60c it's good for 25 amps at the termination.
I don't see a problem.
What does the name plate read?


----------



## telsa (May 22, 2015)

As a general rule, the manufacturer designs his stuff so that it fits #12 conductors -- strictly from a market-competitive point of view.

Think about it. Once the word got out that Man X needs #10 and Man Y needs #12 -- what happens to Man X's sales. They collapse, that's what.

Consequently, I'd pull the pdf on this puppy, pull the numbers of the nameplate... etc.

3600W at 208VAC actually doesn't sound right. 

I'd place my bets that it reads 3600W at 240VAC single phase.

Now that would be a typical reading. ( 15A @240VAC fed by a two-pole 20A circuit )

See how that works out ?

That's why you just never see 3800W heaters. They'd demand #10.


----------



## kolyan2k (Apr 13, 2014)

Southeast Power said:


> What makes you think it's a continuous load?
> #12 is rock solid rated for 30 amps and has to be fused at 20.
> I don't see a problem.
> What does the name plate read?


Its a heater, so its a continuous load. #12 is ok but is 20amp fuse ok for a continuous load of 17.3amps? Name plate would say whatever the website above says basically 



telsa said:


> As a general rule, the manufacturer designs his stuff so that it fits #12 conductors -- strictly from a market-competitive point of view.
> 
> Think about it. Once the word got out that Man X needs #10 and Man Y needs #12 -- what happens to Man X's sales. They collapse, that's what.
> 
> ...


3600 at 208 are the typical heaters, most brands I checked make them 4800-240/3600-208. PDF says 17.3 AMPS


----------



## Dark Knight (Jan 6, 2016)

Firstly, it's not worth it to short change that circuit. If it does trip it'll cost way more to fix than it will to just put in one size bigger now. And if it's running 24/7, it may trip.
However, in CEC #12 is actually good for 25 amps with max fuse size of 20 amps except "as provided for by other rules of this code." Heating being one of those. Overcurrent protection is allowed to be higher than the ampacity of the wire for a circuit supplying only heat. So #12 on a 25 amp breaker would be fine. Something similar in NEC maybe?


----------



## kolyan2k (Apr 13, 2014)

Dark Knight said:


> Firstly, it's not worth it to short change that circuit. If it does trip it'll cost way more to fix than it will to just put in one size bigger now. And if it's running 24/7, it may trip.
> However, in CEC #12 is actually good for 25 amps with max fuse size of 20 amps except "as provided for by other rules of this code." Heating being one of those. Overcurrent protection is allowed to be higher than the ampacity of the wire for a circuit supplying only heat. So #12 on a 25 amp breaker would be fine. Something similar in NEC maybe?


Multiple electricians biding on a job, so forced to save every penny on materials and labor. You go $20 over and job is gone....

I dont think NEC has any upsizing rules for heating...

Basically the question is, would 20amp breaker trip or not on 17.3 amps of cont. load. I really dont think you can call it a violation over that 1.6amps  or am I wrong?


----------



## Dark Knight (Jan 6, 2016)

kolyan2k said:


> Multiple electricians biding on a job, so forced to save every penny on materials and labor. You go $20 over and job is gone....
> 
> I dont think NEC has any upsizing rules for heating...
> 
> ...


Well it's definitely a violation - it's over the allowable amperage. Is it going to trip? Only one way to find out. That's probably not something you want to find out the hard way.


----------



## Southeast Power (Jan 18, 2009)

*H*

As you were about that continuous load:

Branch circuits

If you are sizing branch-circuit conductors for fixed electric space-heating equipment, you must consider these to be a continuous load [424.3 (B)]. The branch-circuit conductors and overcurrent devices for fixed electric space-heating equipment must have an ampacity not less than 125% of the total heating load [210.19(A)(1) and 210.20(A)].

Order 10/2 stranded MC. :thumbsup:


----------



## Southeast Power (Jan 18, 2009)

Dark Knight said:


> Firstly, it's not worth it to short change that circuit. If it does trip it'll cost way more to fix than it will to just put in one size bigger now. And if it's running 24/7, it may trip.
> However, in CEC #12 is actually good for 25 amps with max fuse size of 20 amps except "as provided for by other rules of this code." Heating being one of those. Overcurrent protection is allowed to be higher than the ampacity of the wire for a circuit supplying only heat. So #12 on a 25 amp breaker would be fine. Something similar in NEC maybe?


This sounds.

I'll be in my tent.


----------



## kolyan2k (Apr 13, 2014)

Yeah....pulling 250 feet of 10/2 that cost $300 bucks is not fun, especially pulling and snaking it alone. I know 1.6 over is a violation, but so is 0.1 or 0.5 over and I cant imagine anyone up-sizing the wire over those number. 

And moreover, everything would work more reliably then a wood burning stove even with 25amp breaker and #12 wire


----------



## kolyan2k (Apr 13, 2014)

Southeast Power said:


> As you were about that continuous load:
> 
> Branch circuits
> 
> ...


Would stranded be easier to pull? I usually buy solid so have no clue


----------



## flyboy (Jun 13, 2011)

MXer774 said:


> Alright I want in.
> 
> You never stated if the unit was single or three phase. I see from your calcs it's single.
> Have you even seen the nameplates on these units?
> ...


208 would mean it's 3 phase. 120/208 wye 
If he runs it on single phase it'll only operate at 75%.


----------



## Dark Knight (Jan 6, 2016)

flyboy said:


> 208 would mean it's 3 phase. 120/208 wye
> If he runs it on single phase it'll only operate at 75%.


No, that's not true.


----------



## Cow (Jan 16, 2008)

Seems clear cut to me, it's over 20 amps, it's considered a continuous load, we'd run 10-2.


----------



## frenchelectrican (Mar 15, 2007)

flyboy said:


> 208 would mean it's 3 phase. 120/208 wye
> If he runs it on single phase it'll only operate at 75%.


Not excatally .,, I am not worry about the phases .,, the key issue is voltage .,,


If the OP heater have rating of 4500/3600 watts so we know the 4500 is set for 240 volts and 3600 watts for 208 volt system ( both single and three phase system ) 

You loose about 25% of wattage between 240 and 208 volts.


----------



## telsa (May 22, 2015)

kolyan2k said:


> Multiple electricians biding on a job, so *forced to save every penny* *on* materials and *labor. *You go $20 over and job is gone....
> 
> I dont think NEC has any upsizing rules for heating...
> 
> Basically the question is, would 20amp breaker trip or not on 17.3 amps of cont. load. I really dont think you can call it a violation over that 1.6amps  or am I wrong?


Concentrate on the Labor fraction.

That's where the Big Money is.

It's your running scheme that makes or breaks you.

Ultimately, you make your bones on how clever you are.

Virtually ALL of your competitors will be running the exact same materials. (#10-2 MC)

So, how can 'worrying the materials' solve your budget ?


----------



## kolyan2k (Apr 13, 2014)

telsa said:


> kolyan2k said:
> 
> 
> > Multiple electricians biding on a job, so *forced to save every penny* *on* materials and *labor. *You go $20 over and job is gone....
> ...


Well previous electrician ran Romex for bunch of stuff there, I bet that saved a few bucks and owner is happy. The building call for MC I think


----------



## telsa (May 22, 2015)

Even MC can't compete against Romex.

But, I ask you, was the prior Romex 'work' -- permitted work ?


----------



## telsa (May 22, 2015)

Work that's going to pass under the radar -- is priced for trunkslammers.

The problem with trunkslammer 'craft' is that you can't make a damn thing performing it... except wages.

You are competing against the lying and starving.

That usually means immigrants. By their home-country standards, their craft is tip-top.

See the photos on the Internet as to what tip-top means in the Third World.


----------



## frenchelectrican (Mar 15, 2007)

kolyan2k said:


> Well previous electrician ran Romex for bunch of stuff there, I bet that saved a few bucks and owner is happy. The building call for MC I think


Romex ?? this is in commercal buidling or apartment complex ??


If this is a commercal building the normal SOP is use the MC cable.


----------



## Southeast Power (Jan 18, 2009)

kolyan2k said:


> Would stranded be easier to pull? I usually buy solid so have no clue


That and much easier to terminate.
#10 solid is pretty much like working with a copper nail.


----------



## kolyan2k (Apr 13, 2014)

frenchelectrican said:


> kolyan2k said:
> 
> 
> > Well previous electrician ran Romex for bunch of stuff there, I bet that saved a few bucks and owner is happy. The building call for MC I think
> ...


It's a large 15 story (or more) apartment complex wired with MC and work is in common area with suspended ceiling. I actually haven't checked if Romex is ok there. Will read now

Edit: yeah, cant use romex in dropped ceiling


----------



## MXer774 (Sep 1, 2014)

flyboy said:


> 208 would mean it's 3 phase. 120/208 wye
> If he runs it on single phase it'll only operate at 75%.


You've been in the plane too much 

Pretty sure I can grab two legs of that service and make a single phase circuit.
3Ø @ 208V: 3600/360= 10A
1Ø @ 208V: 3600/208 = 17.3A
3Ø @ 240V: 3600/415= 8.6A
1Ø @ 240V: 3600/240= 15A

As for the OP, you are talking a very small difference in material cost here. So small that it's not going to kill your bid. Your overthinking this. 

Let's see. Your 208V 1Ø circuit (Flyboy) will use 3 #12 or 3 #10
3 #12 = .36/ ft
3 #10 = .56/ ft 
Same size raceway either or.


----------



## kolyan2k (Apr 13, 2014)

Well apparently there is Mass amendment to 334.10 and to 334.12 which I guess allows you to run NM in some cases. Anyone dealt with this? So I can run NM in dropped ceiling if the run is on the same floor? This would be a life saver pulling and snaking the Romex instead of MC

334.10. Amend (3) and insert an exception to read as follows:
(3) Other structures permitted to be of Types III, IV, and V construction. Cables shall be
installed within walls, floors, or ceilings that provide a thermal barrier of material that has at
least a 15-minute finish rating as identified in listings of fire-rated assemblies.
Exception to (2) and (3): For buildings or structures required to be of Type I or Type II
construction, Type NM, Type NMC, and Type NMS cables shall be permitted to be used,
provided that where so applied in buildings or structures exceeding three stories above grade,
circuits run in Type NM, NMC, or NMS cable shall not leave the floor or dwelling unit from
which the circuits originate.
334.12(A)(2). Revise to read as follows:
(2) In dropped or suspended ceilings in other than one- and two-family and multifamily
dwellings, unless run so as to closely follow the surface of framing members, running boards,
or the equivalent, or unless connected to luminaires or other pieces of electrical equipment in
accordance with 334.30(B)(2).


----------



## Helmut (May 7, 2014)

kolyan2k said:


> Multiple electricians biding on a job, so forced to save every penny on materials and labor. You go $20 over and job is gone....


You in the wrong field son.


----------



## Helmut (May 7, 2014)

kolyan2k said:


> Yeah....pulling 250 feet of 10/2 that cost $300 bucks is not fun, especially pulling and snaking it alone. I know 1.6 over is a violation, but so is 0.1 or 0.5 over and I cant imagine anyone up-sizing the wire over those number.
> 
> And moreover, everything would work more reliably then a wood burning stove even with 25amp breaker and #12 wire


what's the voltage drop on using 12AWG, at 17amps at over 250'?

Who did the design work and calcs, you?


----------



## kolyan2k (Apr 13, 2014)

Helmut said:


> kolyan2k said:
> 
> 
> > Multiple electricians biding on a job, so forced to save every penny on materials and labor. You go $20 over and job is gone....
> ...


Not sure what you mean.....dad



Helmut said:


> kolyan2k said:
> 
> 
> > Yeah....pulling 250 feet of 10/2 that cost $300 bucks is not fun, especially pulling and snaking it alone. I know 1.6 over is a violation, but so is 0.1 or 0.5 over and I cant imagine anyone up-sizing the wire over those number.
> ...


Total is about 200-250, it's multiple feeders for multiple heaters


----------



## kolyan2k (Apr 13, 2014)

kolyan2k said:


> Well apparently there is Mass amendment to 334.10 and to 334.12 which I guess allows you to run NM in some cases. Anyone dealt with this? So I can run NM in dropped ceiling if the run is on the same floor? This would be a life saver pulling and snaking the Romex instead of MC
> 
> 334.10. Amend (3) and insert an exception to read as follows:
> (3) Other structures permitted to be of Types III, IV, and V construction. Cables shall be
> ...



So supply sent me the wrong cable lol, instead of stranded MC they sent solid for $300 bucks, which I ended up returning. The way I understand code, I can run NM in commercial applications in suspended ceiling without issues if space is not a plenum. Ill be doing just that.


----------



## readydave8 (Sep 20, 2009)

kolyan2k said:


> The way I understand code, I can run NM in commercial applications in suspended ceiling without issues if space is not a plenum.


That's MA code, not NEC?


----------



## kolyan2k (Apr 13, 2014)

readydave8 said:


> kolyan2k said:
> 
> 
> > The way I understand code, I can run NM in commercial applications in suspended ceiling without issues if space is not a plenum.
> ...


Yes, amendment is right above


----------

