Ex d Zone 1 motor in US

[jrickg]

I have a customer that has purchasesd a Flameproof Zone 1 Ex d motor to be used in a class 1 div 1 area on a piece of waste water treatment equipment.
the end user is stating to use a IEC motor in an 1 D 1 area it must be a zone 0 rated motor per NEC 505.9. Q1 is this the correct code # to apply to this hazardous area applcation? Q 2 is their any US certified body UL or FM to certify this motor to be used in the 1 D 1 area. (side note) Electric Motors are not manufactured to operate in a Zone 0 class area.

 

[rbalex]

Where to start?


The motor as described simply isn’t recognized for use in any location classified as Class I, Division 1 under Articles 500 and 501. It may be possibly be suitable for a “Zone” classified location (Article 505) with appropriate Nationally Recognized Testing Laboratory (NRTL) certification with an “AEx” marking. See Sections 505.9(A)(1) and (C)(2). Of course the location must actually be classified under Zones. Remember, the classification schemes, Division and Zone, are not permitted to be used in the same location. See Section 505.7(B).

Under Section 505.9(A)(3) the motor in a “Zone” location may be found suitable if the Authority Having Jurisdiction believes there is acceptable evidence such as a manufacturer's self-evaluation or an owner's engineering judgment. I wouldn’t count on it.

It is unlikely that a NRTL would certify the motor for Division use since the test standards for Divisions and Zones are sufficiently different.

 

[weressl]

Where to start?


The motor as described simply isn?t recognized for use in any location classified as Class I, Division 1 under Articles 500 and 501. It may be possibly be suitable for a ?Zone? classified location (Article 505) with appropriate Nationally Recognized Testing Laboratory (NRTL) certification with an ?AEx? marking. See Sections 505.9(A)(1) and (C)(2). Of course the location must actually be classified under Zones. Remember, the classification schemes, Division and Zone, are not permitted to be used in the same location. See Section 505.7(B).

Under Section 505.9(A)(3) the motor in a ?Zone? location may be found suitable if the Authority Having Jurisdiction believes there is acceptable evidence such as a manufacturer's self-evaluation or an owner's engineering judgment. I wouldn?t count on it.

It is unlikely that a NRTL would certify the motor for Division use since the test standards for Divisions and Zones are sufficiently different.

Even though it would perform fine.....

 

[bobgorno]

Never, ever trust a sales rep that speaks of the "equivalency" of EEx and AEx or XP.

The best you could possibly do (if the AHJ allows) is use the EEx in a Division 2 location by declaring it a general purpose motor and using the T code to meet the temperature requirements of 501.125(B).

 

[rbalex]

Are you trying to demonstrate your tagline?

 

[petersonra]

you could always pressurize it.

 

[weressl]

you could always pressurize it.

That will not assure that the surface temperature will not exceed the AIT.

Realistically, I agree with you and thought of the same thing, but not according to the Book!

 

[petersonra]

That will not assure that the surface temperature will not exceed the AIT.

Realistically, I agree with you and thought of the same thing, but not according to the Book!

one would think a motor classified for use in zone 1 would have a maximum surface temperature listed.

 

[weressl]

one would think a motor classified for use in zone 1 would have a maximum surface temperature listed.

Absolutely, but you can't take that into account. The test has no validity in the US.

 

[petersonra]

Absolutely, but you can't take that into account. The test has no validity in the US.

are motors used in classified areas required to be listed these days?

 

[weressl]

are motors used in classified areas required to be listed these days?

Division 1? Absolutely.

 

[petersonra]

Division 1? Absolutely.

when did that requirement come about?

 

[weressl]

when did that requirement come about?

501.125 Motors and Generators.
(A) Class I, Division 1.​

​

​

In Class I, Division 1 locations,
motors, generators, and other rotating electrical machinery
shall be one of the following:
(1) Identified for Class I, Division 1 locations
(2) Of the totally enclosed type supplied with positive pressure
ventilation from a source of clean air with
discharge to a safe area, so arranged to prevent energizing
of the machine until ventilation has been established
and the enclosure has been purged with at least
10 volumes of air, and also arranged to automatically
de-energize the equipment when the air supply fails
(3) Of the totally enclosed inert gas-filled type supplied
with a suitable reliable source of inert gas for pressurizing
the enclosure, with devices provided to ensure a
positive pressure in the enclosure and arranged to automatically
de-energize the equipment when the gas
supply fails
(4) Of a type designed to be submerged in a liquid that is
flammable only when vaporized and mixed with air, or
in a gas or vapor at a pressure greater than atmospheric
and that is flammable only when mixed with air; and
the machine is so arranged to prevent energizing it until
it has been purged with the liquid or gas to exclude air,
and also arranged to automatically de-energize the
equipment when the supply of liquid or gas or vapor
fails or the pressure is reduced to atmospheric
Totally enclosed motors of the types specified in
501.125(A)(2) or (A)(3) shall have no external surface with
an operating temperature in degrees Celsius in excess of
80 percent of the ignition temperature of the gas or vapor
involved. Appropriate devices shall be provided to detect
and automatically de-energize the motor or provide an adequate
alarm if there is any increase in temperature of the
motor beyond designed limits. Auxiliary equipment shall be
of a type identified for the location in which it is installed.


This was also in the 2005 and 2002 codes.​

 

[petersonra]

so how would this prevent me from pressuring a zone 1 TE motor and using it in a class 1 div 1 area? isn't by definition a zone 1 motor TE?

it would seem like all that would be necessary is some kind of temperature interlock.

 

[weressl]

so how would this prevent me from pressuring a zone 1 TE motor and using it in a class 1 div 1 area? isn't by definition a zone 1 motor TE?

it would seem like all that would be necessary is some kind of temperature interlock.

Yes, logically it SHOULD be sufficient. Can you cite the Code section that ALLOWS you to do this?

 

[rbalex]

Yes, logically it SHOULD be sufficient. Can you cite the Code section that ALLOWS you to do this?

Theoretically, Section 501.125(A)(2) would permit it. That assumes, of course, that an ?Ex d? motor is totally enclosed. Then the issue is what recognized US American Safety Standard says it is.

One of the early problems with recognizing ?Regular Ex? equipment for US domestic use was that it is NOT required to pass the standards for ?ordinary locations.? The assumption that ?If it?s good enough for classified locations, it must be good enough for common use,? ain?t necessarily so. Part of the ?AEx? marking means that the equipment has also passed the US domestic ?ordinary location? requirements.

Under the philosophy of the previous paragraph, the motor from the OP may not be suitable for any US domestic use at all since it would still be required to be marked per Section 430.7. Those markings are required whether the motor is listed or not.