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#101800 - 05/22/03 07:38 PM Two sources of power in one box
ggardiner Offline
Member
Registered: 10/22/01
Posts: 81
Loc: Calgary, Alberta Canada
I'm looking for some advice from someone in Ontario. I have a consolidation box for hookups to modular furniture, this box is CSA approved and has been on the market for a few years at the moment there is a project in Ontario going on to install the boxes. It has never been an issue of having both utility power and UPS run into these boxes before as the panels and circuits are clearly marked on the box. From the box they travel to plug and play devices such as floor receptacles and office furniture. Now the issue is coming up Ontario doesn't allow it without a devider installed in the box. I say all the wires are rated at the highest voltage and all the devices the consolidation box feeds are remote devices. Thus putting the unit under 12-3034 (b). The consolidation box is to be place under raised floor, the connections within the box are done on terminal strips all of which are not something anyone but qualified personel would be going into. Now in my three years of specing these units I have never had anyone come back with this problem and I was wondering if I missed something in the new Ontario code that would prevent this interpetation in this province?
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#101801 - 05/23/03 09:36 AM Re: Two sources of power in one box
Tony Moscioni Offline
Moderator
Registered: 05/15/01
Posts: 144
Loc: CANADA
It sounds like it would be okay, if in fact the insulation rating is the same.

Without seeing the installation, it appears that it would be in compliance.

Check with the local electrical inspection department for a final interpretation.

12-3032 Conductors in Boxes, Cabinets, or Fittings

(1) Conductors that are connected to different power or distribution transformers or other different sources of voltage shall not be installed in the same box, cabinet, or fitting unless:

(a) A barrier of sheet steel not less than 1.3 mm thick or a flame-retardant nonmetallic insulating material not less than 1.6 mm in thickness is used to divide the space into separate compartments for the conductors of each system; or

(b) The conductors are used for the supply and/or control of remote devices and are insulated for at least the same voltage as that of the circuit having the highest voltage and none of the conductors of the circuits of lower voltages is directly connected to a lighting branch circuit; or

(c) The conductors are used for the supply of a double-throw switch in an emergency lighting system.

(2) Where a barrier is used, it shall be fastened rigidly to the box, cabinet, or fitting, or a device assuring positive separation of the conductors shall be used.

Rationale and Intent for Rule 12-3032. We intend to prevent a condition in which conductors of one power source may become crossed with conductors from a different source and impress another voltage on the circuit, when they are installed in the same box, cabinet, or fitting. Conductors from different sources are allowed in the same box, cabinet, or fitting if they are separated by a barrier of 0.051 inch (1.3 mm); or the conductors are used for the supply and/or control of remote devices and are insulated for the highest voltage in the enclosure (the low-voltage conductors cannot be connected to a lighting branch circuit); or are used for the supply of a double-throw switch in an emergency lighting system.

Tony Moscioni
Electrical Inspector
Electrical Safety Authority
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#101802 - 05/23/03 09:45 AM Re: Two sources of power in one box
ggardiner Offline
Member
Registered: 10/22/01
Posts: 81
Loc: Calgary, Alberta Canada
Thanks for your reply it turns out it was and electrician that was panicing as soon as I talked to the inspector involved the problem went away. I was just afraid there was something in the new code book for Ontario I missed.
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