Control Panel

[kkober@tsinc.cc]

We are having problems in the winter time tripping 20amp breakers in our rental trailers. We are using alot of heat tapes to reduce freezing on our sewer and water hoses. Which is causing trips. We are looking into building some control panels with 12 individual GFCI receptacles. If i use 12 20 amp GFCI receptacles, will a 100 amp main breaker be ok? Every pair of receptacles will have its own 20 amp breaker. So id have 6 20 amp breakers with 1 100 Amp main breaker. Is this ok? Thanks :roll:

see attachment

 

[augie47]

What is the actual load ?

 

[kkober@tsinc.cc]

It can vary. Depends on length of heat tape. Which i havent figured out how many amps per foot that draws. In the process of getting that info.

 

[petersonra]

I would strongly consider in-use covers. It is not unheard of for moisture to cause GFCIs to trip.

Are the breakers that are tripping GFCI breakers?

There is no way to tell you whether what you want to do will work unless you can tell us the load, and even then the rules of the forum might prohibit it.

 

[kkober@tsinc.cc]

well, the heat tape we use is 120V 3Watts per foot. So whats the conversion to get the Amps?? Watts divided by Volts??????

 

[texie]

You have 6- 20 amp, 1 pole breakers. It would appear by the photo that you have a single phase panel. Assuming you put 3 breakers on each phase, that 100 amp main is only going to see 60 amps at worst case. So yes the main is plenty large enough.

 

[texie]

well, the heat tape we use is 120V 3Watts per foot. So whats the conversion to get the Amps?? Watts divided by Volts??????

Yes. But your cable is likely self regulating so the 3 watts per foot is only when it is cold enough.

You should figure a max of 1920 watts (or 640 ft of heat cable) on each 20 circuit to allow for continuous operation requirements.

 

[kkober@tsinc.cc]

Yes. But your cable is likely self regulating so the 3 watts per foot is only when it is cold enough.

You should figure a max of 1920 watts (or 640 ft of heat cable) on each 20 circuit to allow for continuous operation requirements.

Correct, This is at 50* F.....

 

[texie]

As already noted, you should be using "In Use" covers to be code compliant and reliability.

But I'm of the opinion that you should rethink using GFCI. 426.28 only requires GFPE protection of 30mA for heat cable instead of 5mA like a GFCI. This would make for a much more reliable system.

The trick is, that per 210.8 (B)(4) Exception 1, the receptacles would have to be made not readily accessible. You could do this by installing all the receps in an appropriately sized NEMA 3R box with a chase nipple in the bottom large enough for the cord ends to pass thru. Use a standard receptacle a 30 mA GFPE breaker.

 

[kkober@tsinc.cc]

Never heard of GFEP to be honest. Thanks for this help. So GFEP is a type of breaker, not a receptacle? And if i use GFEP then i can use regular receptacles? Im a bit confused, but getting there i believe.

Thanks

 

[texie]

Never heard of GFEP to be honest. Thanks for this help. So GFEP is a type of breaker, not a receptacle? And if i use GFEP then i can use regular receptacles? Im a bit confused, but getting there i believe.

Thanks

The NEC does not require GFCI for heat cables. On only GFPE of 30 mA is required. The issue though is that if you are using cord and plug heat cable, the the receptacle must not be readily accessible if it is not GFCI protected. Hence my suggestion on how to make the receps not readily accessible. 30mA GFPE protection is usually provided by a GFPE breaker. In this scenario you would use a standard receptacle.
Putting heat cable on a GFCI protected circuit is not a wise choice. As it ages, there is often some slight leakage to ground that is above the 4-6 mA threshold of GFCI.

 

[kkober@tsinc.cc]

Well thanks for the help again. Ive just noted that the GFEPs arent even carried in our local electric store, and the cost per GFEP breaker are very expensive. Around $200 a pop!!

Thanks again. Great site, great people, and great help!!!!!!!

 

[kkober@tsinc.cc]

1 more thing. Would this panel need to have a ground rod installed??? Dont have 2014 NEC book yet.

 

[ActionDave]

Yes. But your cable is likely self regulating so the 3 watts per foot is only when it is cold enough.

You should figure a max of 1920 watts (or 640 ft of heat cable) on each 20 circuit to allow for continuous operation requirements.

Gotta be careful with heat tapes. The manufacture will have a max number of feet that you can put on one circuit that will be less than the max number of feet per watts to allow for inrush.

If you have too many feet of heat tape it will trip the breaker even though the total watts per foot is less than the total watts you should have available on a 20A circuit.

 

[StarCat]

Heat Cable Application

Heat Cable Application

Gotta be careful with heat tapes. The manufacture will have a max number of feet that you can put on one circuit that will be less than the max number of feet per watts to allow for inrush.

If you have too many feet of heat tape it will trip the breaker even though the total watts per foot is less than the total watts you should have available on a 20A circuit.

Heat cable is unfortunately one of the most common hack jobs seen on the planet in that it is often installed very poorly and not according to the MFG guidlines which are truthfully not that difficult. It needs to be secured correctly and both ends need to be terminated correctly. This is rarely seen in practice. The note about GFCI not being a good way to feed is absolutely correct. Same reason not to have GFCI on a sump pump or anything that is ultra critical. Raychem is one of the better brands and the one I have run the most of. I generally always hard wire, and the industrial type systems are thermost controlled-protected. IN most cases the cable is always subject to being wet. Heavily worn cable in a harsh environment should be replaced if in doubt.

 

[Jraef]

Never heard of GFEP to be honest. Thanks for this help. So GFEP is a type of breaker, not a receptacle? And if i use GFEP then i can use regular receptacles? Im a bit confused, but getting there i believe.

Thanks

Although used liberally to describe anything with "ground fault" protection, OFFICIALLY the term "GFCI" only means one thing; a Ground Fault Circuit Interrupter knows as a "Class A" device, meaning it is intended to protect PEOPLE from ground fault electrocution, ie the old "radio falling into the bathtub" scenario. That means it must trip at nominally 4mA - 6mA of ground current, never more than 6mA, and interrupt in 1/4 second maximum. GFCI can be a receptacle type device, a unit that mounts and wires LIKE a receptacle, portable device or a circuit breaker WITH a GFCI sensing unit built-in.

When you get to uses OTHER than those where the NEC say that you must have a GFCI (Class A), for instance to protect EQUIPMENT, not people, then it is officially called GFEP, Ground Fault Equipment Protection and can protecting at anywhere from 30mA to 100mA. An often confusing issue on imported equipment is that outside of North America, 30mA is still considered adequate to protect personnel so you often see that described in literature, but here, it dopes NOT pass. This is typically done with breakers that have the GF sensing elements inside, but there are external devices that simply SENSE the GF conditions and are intended to operate some OTHER interruption device. Since the requirement for 1/4 second does not apply to GFEP, that can technically even be a contactor.

By the way since you seem to have not mentioned it, you do know that heat tracing systems are specifically covered under 427.22 right? Because in that section, it says;

427.22 Ground-Fault Protection of Equipment. Ground fault
protection of equipment shall be provided for electric
heat tracing and heating panels. This requirement shall not
apply in industrial establishments where there is alarm indication
of ground faults and the following conditions apply:
(1) Conditions of maintenance and supervision ensure that
only qualified persons service the installed systems.
(2) Continued circuit operation is necessary for safe operation
of equipment or processes.

 

[Sierrasparky]

I seccond using GFEP 30 ma trip. However like others have stated if you use recepts you probably need GFCI. If you convert to a hardwire type setup with proper termination then you could go that way.

Also be ware of the number of feet of cable attached to each other.

 

[Jraef]

I seccond using GFEP 30 ma trip. However like others have stated if you use recepts you probably need GFCI. If you convert to a hardwire type setup with proper termination then you could go that way.

Also be ware of the number of feet of cable attached to each other.

So you are thinking that 427.22 is trumped by the fact that he is using receptacles because they are temporary connections, and because they are 20A they will require a true GFCI? I'm not arguing against that concept, I'm curious as to how an AHJ might interpret that because now that you raise the question, it does expose an ambiguity, something that often leads to AHJs interpretting things differently.

I suppose it makes sense though because there is no way to control WHAT an end user might plug into those receptacles. If so, then I wonder if a proprietary plug and receptacle system could get around that? Might not be practical here, it's just a thought.

 

[iceworm]

well, the heat tape we use is 120V 3Watts per foot. So whats the conversion to get the Amps?? Watts divided by Volts??????

Never heard of GFEP to be honest. ...

... Ive just noted that the GFEPs arent even carried in our local electric store, and the cost per GFEP breaker are very expensive. Around $200 a pop!! ...

As Star alluded, you need to get the mfg installation guide. It will be available on the internet. It will answer all of your questions about installation specifics.

We are having problems in the winter time tripping 20amp breakers in our rental trailers.

You never did say exactly what was tripping; regular CBs, GFI CBs, someother completely unknown. Either way there are problems with the heat trace installations. Changing the panel is not going to fix the problem Heat Trace installations..They will still trip. Or worse yet, they could stop tripping - which means you are just masking potentially dangerous installations.

... Would this panel need to have a ground rod installed??? Dont have 2014 NEC book yet.

The answer will be the same no matter which code cycle you have. Your electrician will be able to advise you on grounding and bonding panels. What does she say?

ice