Hourmeter in Class 1 Div 2 Area

[apat]

We design control panels for class 1 div 2 areas. We have found every component we need to build panels that are suitable for hazardous areas without using a NEMA 7 enclosure, except for a hourmeter.

UL will not certify a panel for use in a hazardous area unless all electrical components in the enclosure have markings showing that it is suitable for use in a hazardous area. However, NEC 501.3b seems to give an exception for meters in hazardous areas if the meter does not have any sliding or braking contacts.

This same exception mentions solenoids and yet hazardous area solenoids are available.

Questions, who one is correct UL or NEC? Can a hourmeter be installed in a class 1, div 2 area without sealing it in a NEMA 7 instrument housing.

 

[petersonra]

Re: Hourmeter in Class 1 Div 2 Area

This is kind of a scary question coming from someone who designs these kind of things.

My first question would be why would you be using NEMA7 in a division 2 area?

 

[rbalex]

Re: Hourmeter in Class 1 Div 2 Area

apat,

To answer your question directly UL writes the product standard ? so they are, by definition, ?correct.? There is no means to compel a NRTL to certify a product apart from the product standard and there is no means to compel UL to change the product standard.

I use the acronym ?ASH? for ?arcing, sparking, and heat producing.? These represent the commonly recognized electrical ignition means in Classified locations. A ?spark? is heated physical material product discharged from an ?arc? or excessive overcurrent condition.

I don?t know the nature of the meters you are considering ? electro mechanical, electronic ? but, unless they have an integral push-button, they are not likely to be an ?arcing? or ?sparking? type source. That leaves ?heat-producing.? That means the device would need to be considered under 501.3(B) (2) or possibly 501.3(B) (3) for some purely electro-mechanical ones.

You may find a product you would like to use regularly, you can have UL or another qualified NRTL to evaluate it and certify it for your use as a recognized component.

From an NEC standpoint, the fact that a solenoid is listed for Division 2 is irrelevant - it isn?t required. Nonetheless, it is relevant to FedOSHA and many other jurisdictions.

Bob,

NEMA 7 is used commonly in Division 2; e.g., see 501.3(B)(1). There are many products the exception doesn't cover.

 

[don_resqcapt19]

Re: Hourmeter in Class 1 Div 2 Area

Bob,

From an NEC standpoint, the fact that a solenoid is listed for Division 2 is irrelevant - it isn?t required. Nonetheless, it is relevant to FedOSHA and many other jurisdictions.

Are you saying that we can't use standard solenoids in Div 2 areas per the OSAH rules, even if the NEC permits them?
Don

 

[petersonra]

Re: Hourmeter in Class 1 Div 2 Area

Originally posted by rbalex:
Bob,

NEMA 7 is used commonly in Division 2; e.g., see 501.3(B)(1). There are many products the exception doesn't cover.

But for control panels, I can't recall ever seeing a NEMA7 control panel in a division 2 area. Especially these days when virtually everything is UL listed for div 2.

I'd be willing to bet he could find some LCD type hour meters UL listed for div 2.

<added>
Plus it mentioned in the OP that he wants UL to certify this thing. That implies to me he works for a UL shop allowed by UL to label such panels. I believe UL has a procedure by which you can use certain parts they approve in advance, even if the listing of the part does not specifically cover hazardous areas. They have a similar procedure for UL508 stuff.

[ March 10, 2005, 12:39 PM: Message edited by: petersonra ]

 

[rbalex]

Re: Hourmeter in Class 1 Div 2 Area

Originally posted by don_resqcapt19:
Are you saying that we can't use standard solenoids in Div 2 areas per the OSAH rules, even if the NEC permits them?
Don

Don,

It does seem like a gotcha to me too. I?ll refer you to FedOSHA?s 29CFR1910.399 (definitions) and let you draw your own conclusions. Check these definitions especially:

Acceptable

Approved

Approved for the purpose


Bob,

We've had a few skid mounted units with integral control panels. A few of the panels have had motor starters, heater contollers, distribution panels, etc. that just don't qualifiy for the exception.

I don't know apat's scope of supply or application. UL indeed has "...a procedure by which you can use certain parts they approve in advance, even if the listing of the part does not specifically cover hazardous areas." I think that's what I said about recognized components.


Edit Spelling

[ March 10, 2005, 01:21 PM: Message edited by: rbalex ]

 

[petersonra]

Re: Hourmeter in Class 1 Div 2 Area

Originally posted by rbalex:

Bob,

We've had a few skid mounted units with integral control panels. A few of the panels have had motor starters, heater contollers, distribution panels, etc. that just don't qualifiy for the exception.

However he indicated that everything else was OK so that would indicate to me he did not have any of these things.

I can see from the definitions how you might well believe that all control panels might well have to be listed, since they are available UL listed. That seems to be stretching the definition a bit though.

Does that mean that the day UL lists any industrial motor, that all motors have to be listed?

<added>
And how would this affect ones ability to use GP devices inside a pressurized enclosure for instance?

would this all but eliminate the ability of any electrician to build up any assembly of parts into a control panel if he were not able to list it?

[ March 10, 2005, 02:33 PM: Message edited by: petersonra ]

 

[apat]

Re: Hourmeter in Class 1 Div 2 Area

Gentlemen,

I appreciate your input and comments.

petersonra, The NEMA 7 enclosure we use is a Crouse-Hinds EMH instrument housing. It has a window through which the hourmeter is visible. Once sealed access is only required if the hourmeter needs replacing. We prefer to err with over protecting our panels vs just getting by.

rbalex, I'm presently waiting for someone from UL to contact me to address this issue and whether we can set up a procedure. That is reason for this inquiry. I'm trying to get different viewpoints to make sure I'm not missing something.
We build panels for remote mounting and also mount them on packages which then require the total installation to comply with UL.

Again, thank you for all comments.

 

[rbalex]

Re: Hourmeter in Class 1 Div 2 Area

Bob,

I misunderstood the direction of your original reply. I took it to mean ??why would you [as in anyone] be using NEMA7 in a division 2 area?? NEMA 250 specifically refers to Division 1 with reference to NEMA 7 enclosures and I though you meant it was ?overkill? in a Division 2 application.

With regard to FedOSHA, I?ll refer you to what has been their ?Standard Interpretation? since 1993. Again you can draw your own conclusion, but I'd pay close attention to the pargraph that starts "In summary,..."

Remember FedOSHA does not have universal jurisdiction. They have no jurisdiction in residential installations unless you have a maid or some such long term ?employee.?

They don?t have immediate jurisdiction in all States either. However, for a State plan to have ?Final Approval? recognition FedOSHA must determine ??that it is providing, in actual operation, worker protection "at least as effective" as the protection provided by the federal program.? So far only sixteen states have received ?Final Approval.?

Over the years the two hardest arguments I?ve ever had to overcome are ?We?ve never had to do that before? and ?We?ve always done it this way.? This is especially a problem when something hasn?t been enforced for years after it?s adoption. People assume lack of enforcement implies legal compliance. I had one client who was routinely melting their low voltage feeders and they consistently attributed it to poor quality material. They refused to accept it was poor engineering by a long time employee who had achieved near god status at the plant.

 

[petersonra]

Re: Hourmeter in Class 1 Div 2 Area

This sounds like it applies to components, but is an assembly made of UL listed components unacceptable if the assembly does not have a UL label on it?

This sounds like any box someone put a relay in would have to be UL listed under UL508a. Surely that cannot be the intent.

 

[rbalex]

Re: Hourmeter in Class 1 Div 2 Area

Intent is a tricky game to play. Ultimately, only judges have the legal right to be mind-readers.

I can tell you the opinion of the previous and current National Director of FedOSHA?s Electrical / Mechanical Safety Division. In short: if it?s under their jurisdiction, anything that can be listed must be. They just don?t have the resources to enforce it.

This is why so many API members are groaning over the fact that GE is now listing motors specifically for Division 2 and anyone who pays attention to Annex A in the 2005 Code should be concerned about the reference to UL 1004.

 

[friebel]

Re: Hourmeter in Class 1 Div 2 Area

To: apat, you have asked the question, " can an hourmeter be installed in a Class 1,Division 2, and you do not mention the group number, so I will assume Group D.
The answer to your question is Yes, I will refer you to the NEC 2002, Section 501.3(B)(3) and it states the following: Transformer windings, impedance coils, solenoids, and other windings that do not incorporate sliding or make-or-break contacts shall be provided with enclosures. General-purpose-type enclosures shall be permitted.
apat, this should answer your question.
The one thing that we need to be concerned with is temperature of the equipment that we are installing in a 1-2-D area. I will refer you to Section 501.(B)(2) Exception: General-purpose-type enclosures shall be permitted if such equipment [other than as providedd in 501.3(B)(1) and if the maximum operating temperature of any exposed surface will not exceed 80 percent of the ignition temperature in degrees Celsius of the gas or vapor involved or has been tested and found incapable of igniting the gas or vapor.

apat, this should answer your question. I will also give you another example of installing equipment in a 1-2-D Classification.
If you will look at Section 501.8 Motors and Generators.
501.8(B) Class 1, Division 2, locations, you can install a three-phase, open-type motor that has no arking devices.
Now, if we can install a three-phase open motor in a Class 1-2-D, you certainly can install an hour-meter that you are concerned with.