supply fan

[secure480]

I have a supply fan that is totally outdoors but is in a area of sewer gas . The supply fan is in a large vent pipe candy cane, that supplies air into a wet well which is a metering pit for waste water. The motor is a explosion proof 3/4 h p .The feed originates from a meter cabinet which is about 25 foot away. The engineer states that the supply pipe which has the motor totally mounted inside is class 1 div 2. A barrier of 3 foot around outside of the pipe is class 1 div 2. ART 501 states I need a barrier within 10 foot. Do I need a EY fitting as stated within 10 foot, if the exception 501.15 exception 4 notes if all 5 conditions are met . He wants a E Y where the feed enters into the meter cabinet panel. I will install a E Y in the non classified area and wanted to install one at the motor (even though) the motor is sealed at the pecker head is this a over kill what do you guys think .The feed is in 3/4 conduit all the way. I have some coming up that are half underground thanks :?

 

[augie47]

Looks as if you meet the exception allowing no seal, but lets wait on on the classified forum gurus to see the post.

 

[kwired]

I have a supply fan that is totally outdoors but is in a area of sewer gas . The supply fan is in a large vent pipe candy cane, that supplies air into a wet well which is a metering pit for waste water. The motor is a explosion proof 3/4 h p .The feed originates from a meter cabinet which is about 25 foot away. The engineer states that the supply pipe which has the motor totally mounted inside is class 1 div 2. A barrier of 3 foot around outside of the pipe is class 1 div 2. ART 501 states I need a barrier within 10 foot. Do I need a EY fitting as stated within 10 foot, if the exception 501.15 exception 4 notes if all 5 conditions are met . He wants a E Y where the feed enters into the meter cabinet panel. I will install a E Y in the non classified area and wanted to install one at the motor (even though) the motor is sealed at the pecker head is this a over kill what do you guys think .The feed is in 3/4 conduit all the way. I have some coming up that are half underground thanks :?

I assume you are referring to 501.15(B)(2), 501.15 itself has no exceptions like you mentioned and (B)(2) is the subpart that should apply to your install.

You said motor is sealed at pecker head. Does that mean the motor itself has some seal between it and the head or there is a seal in the conduit right at the head? Seems a bit nit picking but is what it says.

You still need a conduit seal within 10 feet of either side of the C1D2 boundary if what you have is not a conduit seal.

 

[rbalex]

I assume you are referring to 501.15(B)(2), 501.15 itself has no exceptions like you mentioned and (B)(2) is the subpart that should apply to your install.

You said motor is sealed at pecker head. Does that mean the motor itself has some seal between it and the head or there is a seal in the conduit right at the head? Seems a bit nit picking but is what it says.

You still need a conduit seal within 10 feet of either side of the C1D2 boundary if what you have is not a conduit seal.

It isn't entirely nitpicking. Typically, an explosionproof motor has a factory seal between the motor housing and the motor terminal box. Thus Section 501.15(B)(2) Ex No. 4 doesn't apply since there would be no seal between the raceway and the terminations.

"A camel is a horse designed by a committee." I happened to be on the API tech committee that proposed Section 501.15(B)(2) Ex No. 4. In fact, I wrote the original draft before all the wordsmithing. The original intent was to avoid explosionproof raceway seals where intermittent Division 2 envelopes occurred along long outdoor pipeway runs. The pipes did not usually create the envelopes themselves but they might be proximate to other process sources. Ever since CMP14 declared explosionroof boundary seals weren't necessary in the last sentence of the main text of Section 501.15(B)(2), possibly Ex No. 4 may be due for a minor rewrite.

 

[secure480]

suppl fan

suppl fan

the motor is sealed or factory sealed at the motor

 

[secure480]

suppl fan

suppl fan

thanks gentlemen, the motor is sealed and rbalex is correct made me think more about 501.15 b exception 4 thanks again