XP / I.S. Pressure Transmitter wiring in Class I Division 2

[justdavemamm]

I have Process Skid to be wired. It is going in a Class I Division 2 area. All instruments & devices (mostly 4-20ma loop devices) on it, except one, are rated Non-Incendive. I'll have a NEMA 4X junction box with only terminals in it where everything is wired back to. Wiring from the JB to off the skid, to the customers non-classified control room, is the customer's responsibility.

The one device that is not N.I. is listed for Class I Division 1, XP or Intrinsically Safe wiring. It is a loop powered (4-20ma) pressure transmitter. I don't want to do I.S. as I would need to have a separate unique conduit from it to the JB, separated wires in the JB and then another unique conduit into the safe are where the I.S. barrier (or isolator) is.

If it were a C1D1 area, I know for XP wiring I would need a seal-off at the device and all fitting / flex must be listed for C1D1.

But it's a C1D2 area. While I know (?) that a seal-off is needed at the device, what about after that to the JB and then control room? Do I need to do the whole run XP and not enter the JB that has terminals for the N.I. items?

Or do I just put a seal-off going into the JB (from the conduit to the XP device)?

Do I need XP listed fittings / flex after the device seal-off ?

 

[don_resqcapt19]

If this is a transmitter with out contacts and its normal operating temperature is less than 80% of the ignition temperature of the products in the area it will not need a seal at the transmitter or at the junction box (assuming conduit is less that 2"). The only seal that is required would be at the boundry. Explosionproof fittings are not required for division 2 areas for this application.

 

[justdavemamm]

I've just gotten a factory manual which says:

"Make all electrical connections (use #14 -18 AWG) via ?? conduit to the terminal strip inside the cover. Install an approved seal-plug adjacent to the transducer as part of the conduit run to prevent propagation of flame through the conduit system."

There is no mention about contacts or temperature.

I was mistaken before when I said it could be wired I.S., it cannot.

It isn't C1D2 N.I. rated, just: "Explosion-proof: Class 1, Divisions 1 & 2, Groups C & D."

Therefore, since it must have a seal at the device, what about after the seal to my JB. Must I use approved XP fittings / XP conduit. And then can I go to the same JB as my N.I. instruments ?

- Dave

 

[don_resqcapt19]

Explosion proof fittings are not required in Class I Division 2 areas. The exception to this would be any fittings installed between a seal and an enclosure that is required to be sealed. Seals are not required at junction boxes unless the conduit is 2" or larger. The code rules do not require a seal at this instrument per the exception to 501.105(B)(2) and 501.15(B)(2). That being said the instructions, if they are listing and labeling instructions, override the code and require the use of a seal at the instrument.

 

[justdavemamm]

Thanks for the update. I thought that may be the case. Installing instruments / devices rated XP only in a C1D2 has taxed my knowledge and understanding of the code.

 

[jcross]

Explosion proof fittings are not required in Class I Division 2 areas. The exception to this would be any fittings installed between a seal and an enclosure that is required to be sealed. Seals are not required at junction boxes unless the conduit is 2" or larger. The code rules do not require a seal at this instrument per the exception to 501.105(B)(2) and 501.15(B)(2). That being said the instructions, if they are listing and labeling instructions, override the code and require the use of a seal at the instrument.

Are seals required at junction boxes(non-explosion-proof) in C1D2 areas where the conduit entry is 2" or larger? I thought only 501.15(A)(1)(2) was where this was a requirement.....

 

[don_resqcapt19]

Joe,
You are correct, that rule only applies in Division 1. Thanks for catching that.