Radient Heat Damp location?

bassphisher · Jan 9, 2006

I am inspecting a hallway that was installed between two buildings in an assisted living center.This is not your normal hallway.It is more like an awing with sides.Tent like with 2x2 metal frame bolted to the sidewalk.The sides of this tent-hallway does not touch the sidewalk so when it rains the wind can blow water underneath.Its all piped in with emt and set screw fittings,4 square boxs.They want to install 8-3000watt/208v radiant heaters.These will be fed from a the only panel in this building.It has a 175Amp main breaker.I am going to ask them to do a service calculation since they are attempting to add 100Amps of continuous load to this panel.I suspect that they do not have enough ampicity for this additional load.They want to feed these heaters with 2-60Amp breakers #6 wire.Violation of 424.3(A).They want to tap these #6s with #12s to feed a dual fused switch(sty)that will feed an individual receptacle that they will plug the heaters into.Seems like their are a lot of violations here.Also no lights are installed.Its supposed to be day use only,for physical therapy.Your help is appreciated.

[ January 09, 2006, 01:43 PM: Message edited by: bassphisher ]

charlie b · Jan 9, 2006

Re: Radient Heat Damp location?

What help would you like? It seems to me that you are already aware of a number of problems. This would be a good time to, "just say 'no.' "

bassphisher · Jan 9, 2006

Re: Radient Heat Damp location?

I would like opinions on the damp location.Do we agree or disagree?
If their was enough ampicity would you allow these to be cord connected?
You cannot tap multioutlet branch circuits.Right? 210.19(2)Technically its a feeder to the sty and a branch circuit from the sty to the outlet?
Do they have to install lights?
Can the feeder size be based on actual useage and not va per square foot?The estimater said this is how he did it and other inspectors say that this is ok.
The only thing that is left to do on this job is to hang the heaters.I am new to inspecting and I am not used to telling contractors that what they just finshed installing is all wrong.Does this get easier with time?

[ January 09, 2006, 02:58 PM: Message edited by: bassphisher ]

benaround · Jan 9, 2006

Re: Radient Heat Damp location?

bassphiser,

I don't see the 424.3A violation,branch circuits are after the final OCPD,not the feeder.
The damp location,you have to make that call,It would be nice to know if the owners are going to continue to upgrade the area,i.e. real walls etc.
Good Luck,

George Stolz · Jan 9, 2006

Re: Radient Heat Damp location?

Holy jeez, you gotta lotta info, so you got a looooooong post from me!

They want to feed these heaters with 2-60Amp breakers #6 wire.Violation of 424.3(A).

Agreed. I believe they could use 50's (commercial), but four heaters pulling 15 amps apiece would overtake that. So, they need a third circuit.

Now, that said, I would say that 424.3(B) seems to fully preclude using taps. It even takes the time to mention that 240.4(B) can be applied. It doesn't seem that tapping is an option.

An easy solution would be 60 amp fused A/C disconnects. Then the units could be fused down to their appropriate unit nameplate ratings.

You cannot tap multioutlet branch circuits.Right? 210.19(2)

This is not a multioutlet branch circuit.

(2) Multioutlet Branch Circuits. Conductors of branch circuits supplying more than one receptacle for cord-and-plug- connected portable loads shall have an ampacity of not less than the rating of the branch circuit.

Do they have to install lights?

That's a building code issue, not NEC. (Unless I missed my resi/comm assumption.)

Can the feeder size be based on actual useage and not va per square foot?The estimater said this is how he did it and other inspectors say that this is ok.

The feeder should be sized according to the calculated load (215.2(A)(1)). I believe you're thinking of the general lighting & receptacle load for the service, which is calculated by the area of the structure. If the feeder does not power general lighting and outlets, it doesn't need to worry about it.

The only thing that is left to do on this job is to hang the heaters.

At least, that's what they think, right?

I am new to inspecting and I am not used to telling contractors that what they just finshed installing is all wrong. Does this get easier with time?

Well, consider this the numbing agent for the rest of your career. Your skin will be good and thick when you're done.

George Stolz · Jan 9, 2006

Re: Radient Heat Damp location?

Originally posted by benaround:
I don't see the 424.3A violation,branch circuits are after the final OCPD,not the feeder.

Genius!

bassphisher · Jan 10, 2006

Re: Radient Heat Damp location?

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Can the feeder size be based on actual useage and not va per square foot?The estimater said this is how he did it and other inspectors say that this is ok.This is according to the estimator,I have not talked to any other inspectors yet.

The feeder should be sized according to the calculated load (215.2(A)(1)). I believe you're thinking of the general lighting & receptacle load for the service, which is calculated by the area of the structure. If the feeder does not power general lighting and outlets, it doesn't need to worry about it.

Frist of all thanks George for time that you spent answering my questions,I really appreciate it.
I may have not been very clear on one (or two) of my questions.
I said feeder wich was a mistake on my part.What I should have said is service.The building has a service with a 175A main breaker.I am going back to check the service wire size.And they want to add 100A of continuous load.They think that this is ok(based on actual useage)and that they do not need to do a load calculation based on va per square foot.I have been digging for the answer in the code to see if this is true and I think that I may have found one.It seems like 220.87 allows you size a service on actual demand.Do you agree or am I reading this wrong?With this being said 220.87(2) talks about multiplying the demand by 125%.If I interpreted this correctly then I would multiply the demand by 125% and the continuous load(heaters)by 125% and add them together.Right?

If their was enough ampacity would you allow these to be cord connected?

What is their reasoning behind wanting to cord connect them? Are they frequently interchanging them? It seems as though they're fixed in place, they should be hard-wired, IMO. 400.7 & .8
What is their reasoning behind wanting to cord connect them? Are they frequently interchanging them? It seems as though they're fixed in place, they should be hard-wired, IMO. 400.7 & .8

The heaters come from the factory with cords on them.
I agree I was just looking for confirmation.

Are they rated for wet locations?

Yes
Thanks

[ January 10, 2006, 11:40 AM: Message edited by: bassphisher ]

bassphisher · Jan 10, 2006

Re: Radient Heat Damp location?

Originally posted by benaround:
I don't see the 424.3A violation,branch circuits are after the final OCPD,not the feeder.

Your right,I skipped a click.This part of the installation is a feeder.I have to admit I need to review my tap rules.I wish I could draw and post a diagram for clarification.
They installed #6s on a 60a breaker.At each heater they installed a 4 11/16 connecting to a 4 sq with an offset nipple.The #6s are tapped in the 4 11/16 with #12s for the line side of the sty's.Off the load side of the sty's are #12's that go back through the offset nipple to feed a single outlet mounted on the 4 11/16 box.
No foul?

bassphisher · Jan 10, 2006

Re: Radient Heat Damp location?

Originally posted by georgestolz:
Holy jeez, you gotta lotta info, so you got a looooooong post from me!

I try to provide plenty of info. so that I can paint a good picture.And it seems like their is soo much wrong with this mess. :roll:

George Stolz · Jan 11, 2006

Re: Radient Heat Damp location?

It seems like 220.87 allows you size a service on actual demand.Do you agree or am I reading this wrong?

Without seeing the 2005, I'm looking at '02's 220.35, which is probably the same. I'd say yes, it allows for measuring the existing load under the NEC's terms. I'd follow those stipulations to a tee.

...by 125% and add them together.Right?

I believe so.

The heaters come from the factory with cords on them.

Well, that answers that, the cords can stay.

Conclusion:

The 10 wire on the 60 amp circuits violate 424.3(B), IMO. If they use the right equipment, they don't need the taps anyway.
Each heater is worth 18 amps (corrected for continuous load), so they can have three per 60 amp circuit. That's three circuits.
Find out what the nameplate max OCPD is for the heaters.
Watch their load calc closely.

Frist of all thanks George for time that you spent answering my questions,I really appreciate it.

You're welcome, I hope I did more good than harm, but it'd be good to hear from others before running to the bank with my opinion.

George Stolz · Jan 11, 2006

Re: Radient Heat Damp location?

Quick thought as I run out the door: It couldn't be over 50 amps, due to one of the sections we looked at above.

So they're back to taps. Which they can't use.

Sounds like they're up a creek, IMO.

Radient Heat Damp location?

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