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V.I on Rigid PVC junction box

PostPosted: Fri Oct 17, 2014 7:31
by Frank
Hi,
Conducting a V.I. on heat detectors. Electrician installed 3 moisture proof heat detectors inside a freezer/cooler. He installed rigid PVC conduit Pipe and PVC junction boxes. How can I test a proper ground when conducting V.I.

Thank you for your help.

Re: V.I on Rigid PVC junction box

PostPosted: Sun Oct 19, 2014 10:43
by FIRETEK
A separate ground wire should have been run to each box. Every weatherproof box I've seen has a ground strap in it. The ground wire must be properly terminated to the ground connection. Check to make sure that the heat detector is rated to go below 0 degrees Celsius. If it's not, then the installer will either have to find one or use a properly rated linear type heat detector (Protectowire).

Re: V.I on Rigid PVC junction box

PostPosted: Sat Oct 25, 2014 11:33
by Frank
Thank you for your response.
I have spoken with the electrician about the ground wire. The ground wire is connected to the first box that is EMT. He ran the ground wire through the new PVC back boxes and conduit. He said that the electrical code has changed and that PVC back boxes do not have to be grounded. I have read on the forms that every fire alarm device back boxes in Canada requires to be bonded to ground. Can you please advise which codes and section to reference on this matter.
Thank you

Re: V.I on Rigid PVC junction box

PostPosted: Sat Oct 25, 2014 4:21
by FIRETEK
Tell him to check Clause 32-104. Also tell him to refer to Clause 10-404. He must provide a ground connection at all outlet/equipment back-boxes. I doubt the electrical inspector would agree with his interpretation of the CEC.

Clause 32-104(1) states:

"Exposed non-current-carrying metal parts of electrical equipment including outlet boxes, conductor enclosures, raceway, and cabinets shall be bonded to ground in accordance with Section 10."

If the "Electrical equipment" (i.e. heat detectors) you're using are the "Thermoflex" type (manufactured by Fire Detection Devices), these are all metal units and must be individually bonded to ground.

Re: V.I on Rigid PVC junction box

PostPosted: Mon Oct 27, 2014 11:40
by Frank
Yes, the heat detector is a Thermoflex manufactured by Fire Detection Devices. The ones that were installed had pigtail leads and the plate of the device is plastic.

Re: V.I on Rigid PVC junction box

PostPosted: Mon Oct 27, 2014 11:52
by FIRETEK
Last time I checked, aluminum is still an excellent conductor of electricity. :)

Re: V.I on Rigid PVC junction box

PostPosted: Mon Oct 27, 2014 9:56
by FIRETEK
I should add that the detectors you're Verifying are NOT ULC Listed for use in the type of environmental conditions to which they will be exposed. They are "tested" to -20C, but only for a "soak" period of 24 hours, after which they are returned to normal room temperature and tested for operation. For you to be able to meet the criteria of the Installation Standard (and Verify the installation properly), you would have to use the more expensive EWT badged model.

I encountered a similar situation here in Delta, B.C. where a contractor installed the wrong type of Protectowire. When I informed him that there was only two models of the cable that were rated (and ULC tested) to operate in a freezer type environment, he called in another Verifier that accepted the installation where I wouldn't.