Switched Neutral Manual Transfer Switch

Three pole transfer switches with overlapping neutral contacts.

Switched neutral manual transfer switch.

With a switched neutral the generator set can be wired as a separately derived system to the load and normal power supply. A manual transfer switch is installed next to the main service panel to override the normal electrical service with power from a backup generator during a power outage. If there is no grounded neutral conductor run to the transfer switch or if the transfer switch does not switch the grounded neutral conductor then the generator is not a separately derived system. The new reliance panel link x series is a double pole manual transfer switch with an exclusive third pole for the neutral that switches sequentially.

In this configuration the neutral is not solidly connected through the transfer switch but switched. The generac 6297 30 amp switch neutral kit for manual transfer switches is designed to enable manual transfer switches up to 30 amp to isolate the utility and generator neutrals. Also the neutral is designed to be switched simultaneously with the switching of the load carrying phases. This type of transfer switch offers many advantages including the following.

This switched neutral kit can be used in single phase manual transfer switches up to 30 amps 125 250v. For the generator to be considered a separately derived system the supply to the transfer switch must include a grounded neutral conductor and the transfer switch must switch the grounded neutral conductor example a 4 pole transfer switch for a 3 phase 4 wire system. This is known as a switched neutral system and the neutral switching can be open or overlapping closed. If you cannot lift the bond disconnect the ground wire to the transfer switch at the generator or don t run a ground wire at all.

It operates with little or no arcing which minimizes the risk of erosion or degradation of the neutral contact. One disadvantage is the design and construction of the neutral pole and contacts. The generator can optionally be grounded to a rod. A premises wiring system whose power is derived from a source of electric energy or equipment other than a service.

The switched neutral kit can upgrade most manual transfer switches from non switched neutral to switched neutral as required b y certain municipalities electrical inspectors and generators. According to the 2011 national electrical code nec a separately derived power system is. The subpanel will still be grounded from the unswitched ground wire from the main panel. How to install a manual transfer switch for backup system in 16 steps.

However a 3 pole transfer switch with overlapping neutral contacts has several drawbacks.