My portable generator has a bonded neutral (to ground). I want to hook this unit up to the house, and have already installed an interlock to ensure there is no back feed. The neutral is not switched by the interlock, only the two hots; the neutral is hard wired. Because there is a connection to ground in the main panel, I understand it should be floating on the generator, to avoid them being tied together in two places. But when using the generator as a portable unit, they should be bonded. So I don't want to break the bond at the generator. My planned solution it to not connect the ground wire at the inlet receptacle (on the house), and only connect the two hots and the neutral to the house. This will eliminate any loops, without modifying the generator itself. What thickest ye? Greg
I connected both phases, neutral and ground from the service panel to the outlet that the generator plugs into.. This would ground the generator frame and protect you in the event the frame became live. What you don't want to do is run a separate ground but use the one from the service panel.. A live generator frame could be a deadly hazard.. Reliance Controls 30 Amp 10 Circuit Manual Transfer Switch Kit-31410CRK - The Home Depot
Thank you. But I am not sure this is right - nor am I sure it is wrong. The problem I see with what I understand you did, is that the ground and neutral on the generator cord are now parallel circuits. So the "return" from the neutral of the house will go through both the ground wire and the neutral to the generator. This would increase the chance of shock, rather than decrease it, could cause havoc with GFCIs, etc. I think most people do it as you suggest, and it works fine. I am thinking the best plan is to do as I was thinking, but then physically ground the generator, separate from the house. But I am still listening, thanks for the input. Greg
Sorry forgot to mention this.. Found online to save typing: "Most portable generators are bonded neutral. The reason being is the unit then is grounded to the frame so there is no shock hazard. Manufacturers know that most consumers use them as without grounding them properly due to their portability. They should be changed to floating neutral when you are installing to the transfer switch."
THANK YOU! So, I am thinking that my idea of not carrying the ground through to the house panel accomplishes the same purpose, without generator modification? Greg
You avoid the neutral problem but leave the generator ungrounded.. You could attach a ground wire from the generator to the ground rod your service uses or break the ground to neutral connection at the genny.. Whatever works for you..
Greg if you want to be able to keep portability of the generator and break the neutral-ground bond for house use look into a simple knife switch disconnect that could be worked into wiring of the generator. You could use a single pole of an HVAC service disconnect.
Greg, You can also "dead spike" a grounding bar in the ground or your houses grounding bar and run a heavy alligator clip/connection to it if you choose to the frame of the generator. But Ray has a good point, you can leave it ungrounded. I'm not an electrical engineer but I have shocked myself once or twice!
OK so thanks bushpilot for reminding me to remove the ground to neutral jumper on my generator.. I am a licensed electrician so I know better than this! I simply forgot to remove the jumper.. It took all of 10 minutes and this jumper is located in the generator head which is removed by 2 small bolts then remove the white wire that goes to the ground screw and winding.. I verified before and after with my multimeter then hooked up the generator to the transfer outlet and checked voltages.. All looked fine (which it did before) and took a shower with the furnace for hot water and the well pump on to create load and all is well.. Attached pics to show this wire I removed.. Easy to put back if I ever wanted to run the generator without transfer switch.. Ray
After seeing Ray's pictures it'd be real easy to add an automotive toggle switch to the peckerhead of the generator, just use the same size wire to increase the length of the leads, couple spade and ring terms and you're in business.
Did think about this but will probably always connect to the transfer outlet plus very easy to reinstall the jumper..
