Mike Dolt Enterprises
Mike Dolt Enterprises
User: hotwire62, Location: Georgetown Ca. USA
Asked on: Tuesday, March 22, 2011 at 11:44 pm EDT
Answered on: Tuesday, May 14, 2024 at 3:08 am EDT
Question: one of my customers was running his generator connected through a GE safety switch/ manual transfer switch when utility power came back on one arc fault breaker was damaged, two garage openers , one motion sensor switch and electronics on gas range ,He has used the transfer switch for three years with no problems ,I have the same one on my house and use it all the time in the winter and have had no problems , somehow a surge had to have come through the neutral as the hots are completly disconnected from utility when in generator position how would this happen and would it be wise to put in a seprate knife switch in to disconnect neutral from the utility when gen is running.
How the Surge Could Have Occurred
In the manual transfer switch, the neutral is typically connected to the utility supply when in utility mode. However, when switched to generator mode, the neutral is disconnected from the utility and connected to the generator.If a surge occurred on the utility supply while the transfer switch was in generator mode, it could have traveled through the neutral and reached the generator and connected loads. This could have caused the damage to the arc fault breaker, garage openers, motion sensor switch, and gas range electronics.
Why It Might Be Wise to Add a Separate Knife Switch for Neutral
Adding a separate knife switch to disconnect the neutral from the utility when the generator is running would provide an additional layer of protection against surges. By isolating the neutral, you would prevent any surges that occur on the utility supply from reaching the generator and connected loads.
Procedure to Add a Separate Knife Switch for Neutral
1. Install the knife switch in the main electrical panel, downstream of the utility supply and upstream of the manual transfer switch.
2. Wire the knife switch as follows: Connect the line side (L) to the utility neutral wire. Connect the load side (L1) to the neutral wire that goes to the manual transfer switch.3. When the generator is running, turn off the knife switch to isolate the neutral from the utility.
Additional Considerations: It is important to ensure that the knife switch is rated for the current and voltage requirements of your system. The knife switch should be clearly labeled to prevent accidental activation.* Consider using a surge protector on the generator output to provide further protection against surges. Flag for review