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#101653 - 08/08/02 12:30 PM installing a transfer switch
jdevlin Offline
Member

Registered: 08/07/02
Posts: 400
Loc: welland ontario canada
I would like to install a whole house transfer switch. The current setup is a 100a main disconnect (with fuses)connected via a 2 in. stub out the side to a breaker panel. I was thinking I could remove the wires from the bottom of the disconnect. Install a transfer switch below the main disconnect. Run new wire from disconnect down into the transfer switch and up to connect to the wires removed from the disconnect.

What size wire should I be using? Do I need split bolts to connect or are the big blue wire nuts OK?
What brand of transfer switches does anyone here reccommend? What price ranges exist?
I live in Ontario Canada.

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#101654 - 08/08/02 03:30 PM Re: installing a transfer switch
Tony Moscioni Offline
Moderator

Registered: 05/15/01
Posts: 144
Loc: CANADA
Transfer Devices


Under no circumstances shall a generator be connected to any portion of a wiring system except where it is connected through a transfer device that makes it impossible for the generator to feed back into the normal power supply. [Ontario Electrical Safety Code (OESC) 6-106, 14-612, 75-612].



Where a double throw transfer device is mounted at a service entrance, the transfer device shall be located on the load side of the service entrance switch [OESC 75-612 (3)(d)], except as follows:



A transfer device may be located on the supply side of an existing consumer’s service entrance at a building provided:



· it is approved for service entrance use [2-032] (see note 1).

· the consumers service ground conductor connection is relocated to the transfer device and the neutral bond screw or jumper in the existing service box is removed. [10-204(1)(a)(b)(d)]

· a bond conductor is present between the new transfer device and existing service equipment. [10-400]

· this transfer switch shall be treated as the consumers service box for code interpretation purposes.



Note 1 - There are some transfer devices bearing markings such as “Suitable for service use” which is an American NEC marking not applicable in Ontario. Manual transfer devices approved for service entrance use in Ontario shall be approved to CSA Standard C22.2 No 4, shall be marked “Suitable for use as service equipment” (note the subtle difference in wording), shall meet the OESC definition of a Service Box (switch & fuse, or circuit breaker), and shall have the neutral assembly bonded to the enclosure with provision for separate connections of the line and load neutral conductors and the service ground conductor.



A pole top switch may also be located on the supply side of a consumer’s service entrance provided it is installed in accordance with OESC Section 75.



Standby generator neutral grounding and switching issues


The following is intended to provide some guidance in clarifying where the neutral conductor from a standby generator shall be switched and where it shall be solidly connected at transfer devices. The following information is consistent with Electrical Inspection Bulletin 10-10-*.



Load side of consumer’s service entrance



Where the generator transfer device is located on the load side of consumers service entrance equipment and the generator neutral is connected to the generator frame, the neutral shall be switched in the transfer device to ensure the neutral is connected to the ground electrode at only one point at any given time. [OESC 10-204(1)(d)].



Experience has shown that most small portable generators have the neutral conductor connected to the generator frame. CSA Standard C22.2 No 100-95 requires the status of the neutral conductor to be marked on each machine as follows: “Neutral Floating” or “Neutral Bonded To Frame”. Where provision has been made by the manufacturer to connect or disconnect the neutral conductor from the machine frame, such provision shall be clearly indicated in the marking. (Older machines may not have this marking.)



For consistency, Electrical Inspectors have been advised to treat all portable generators as having the neutral bonded to the frame unless evidence is provided to the contrary.



Supply side of consumer’s service entrance (pole top switch)



Where the generator transfer switch is located at a pole top on the supply side of consumers service entrance equipment, the OESC permits the neutral to be multi grounded [10-204(1)(a)(b)(c)]. The neutral shall not be switched at the transfer device, but shall be solidly connected.



Where the generator transfer switch is approved as consumers service entrance equipment, the neutral is also not required to be switched and shall be solidly connected

Under no circumstances shall a generator be connected to any portion of a wiring system except where it is connected through a transfer device that makes it impossible for the generator to feed back into the normal power supply. OESC 6-106, 14-612, 75-612.



A licensed electrical contractor knowledgeable in this type of work can advise of other acceptable installations complying with the OESC.



The installation shall comply with the requirements of the OESC with respect to conductor type and size, circuit loading and demand factors, grounding and bonding, wiring methods, protection and control, etc.



We strongly recommend consulting and hiring an electrician with a certificate of qualification, and who is knowledgeable in this type of installation should you decide to proceed with the work.



An incorrectly wired installation may result in life threatening shock or fire hazards to both the building occupant and electrical utility personnel.



All installations of electrical equipment are subject to the inspection requirements contained in the OESC. A reputable electrician will look after this.


Tony Moscioni
Electrical Inspector
© Electrical Safety Authority - 2002

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#101655 - 08/08/02 04:20 PM Re: installing a transfer switch
jdevlin Offline
Member

Registered: 08/07/02
Posts: 400
Loc: welland ontario canada
Under no circumstances shall a generator be connected to any portion of a wiring system except where it is connected through a transfer device that makes it impossible for the generator to feed back into the normal power supply. [Ontario Electrical Safety Code (OESC) 6-106, 14-612, 75-612].


Where a double throw transfer device is mounted at a service entrance, the transfer device shall be located on the load side of the service entrance switch [OESC 75-612 (3)(

It was my intent to mount a proper transfer switch on the load side of the main disconnect.

From all the rest I gather that the neutral should also be switched in my case.

Now can you reccommend a brand of switch?

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#101656 - 08/08/02 04:24 PM Re: installing a transfer switch
jdevlin Offline
Member

Registered: 08/07/02
Posts: 400
Loc: welland ontario canada
In case it wasn't clear the main disconnect is in a separate enclosure from the main breaker panel. They are mounted side by side joined by a 3 inch long conduit nipple.

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#101657 - 08/09/02 01:26 PM Re: installing a transfer switch
Tony Moscioni Offline
Moderator

Registered: 05/15/01
Posts: 144
Loc: CANADA
Here is a list of 8 suppliers that come to mind. That's not to say there are not any others that would be acceptable. Remember, to check for the approvals label on any product you purchase, and as well, an application for electrical inspection will be required.


G.E., Zenith ZTX residential / Light Commercial grade automatic transfer switch, 3 pole, Nema 1 Enclosure

ASCO, 220 Volt, 3 Pole, Nema 1 Enclosure

Square D, manual transfer switch, contactor type

Westinghouse, manual transfer switch, 240 volt, 3 pole, double throw safety switch

Reliance Controls LOAD-SIDE™ TRANSFER SWITCHES

Cutler Hammer Transfer Switches AT 3 Pole 240 v 60 hz Nema 1

Kohler, 240 Volt, 3 Pole, Nema 1, Molded Case Style

G.E., manual transfer switch, contactor type, 3 pole

Tony Moscioni

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