We recently lost power for 3 days in the great ice storm 12/21/13. On day 3 we borrowed a generator and we ran extension cords to run the refrigerators and a couple lights and I cobbled into the furnace, taking care to turn off the furnace breaker to avoid backfeeding power into the grid. Now in preparation for the next storm, I want to ready myself. I happen to have a hot tub wired for 220V, and the hot tub line has an additional breaker (GFI) on it outside the house. I wired it myself, forget the gauge of the wire but I had an electrical engineer at work advise me on the proper gauge. Now I’m thinking, all I have to do in the next outage is get a 220 plug and wire to put in the generator, connect the wires to my outside box for the hot tub, and use the hot tub wire to backfeed to the main panel and power the whole house. Of course, I’d disconnect the main breaker before starting the generator. Plus I’d probably turn off some of the less than essential breakers on the main panel so as not to overwork the generator or overheat the hot tub to panel wires.
The question is- would that give sufficient protection to the utility crews as they restore power? If not, how does a transfer switch disconnect me from the grid more effectively than throwing the main breakers?
The point of the transfer switch is that, once wired correctly, it prevents you from making a mistake that might endanger others, since it physically prevents the generator from being connected to mains power.
I assume the plan you have outlined will technically work, but it leaves it up to you to remember to turn off the main breaker. For this reason, it’s probably not up to code in your area. When the power goes out in a snowstorm at 3 AM and you’re struggling to get the heat back on, are you sure you’ll remember to flip the main breaker? What if it happens while you’re out of town and your wife or kid(s) try to do it?
No question it wouldn’t be up to code. I’m certain that I would never forget to turn off the main breaker. Yeah, if I was laid up or dead I’d be less certain that others would turn off the breaker. I’ll probably spring for a transfer switch.
That’s a really lousy way to wire up a generator, and it’s definitely not to code. It will work in the sense that if you don’t forget to turn off the main breaker it won’t blow up and won’t cause any harm to utility workers, but that’s a big if. You are one switch throw away from having really bad things happen. You are also creating a hazard if the generator can supply more current than the branch circuit out to the hot tub is designed to handle.
The proper way to do it is to get a sub panel off of the main panel that has all of the things that you want to power the generator with on it. The transfer switch is then installed between the main panel and the sub panel, and the generator is wired into the system through the transfer switch. Then, when the power goes out, all you need to do is throw the transfer switch. You don’t need to remember which breakers to shut off to prevent overloading your generator and you don’t need to worry about back-feeding into the main line where you could kill someone.
Your method is cheap and stupid. And that’s my professional opinion as an electrical engineer with over 25 years of experience.
I think in the moment of necessity we all find ways around the codes. There are a buttload of people that run their generators through their dryer plug. If you haven’t done the proper thing and installed the transfer switch and the ice storm hits, you do what you gotta do. The concern about overheating the hot tub line is very real and probably will be the driving factor in getting the proper switch installed.
That’s also my amateur opinion as someone who knows a little bit about electricity and has done a lot of his own electrical work (up to code) during home renovations.
Linesmen have been killed due to generators installed as proposed in this thread.
Here is an OSHA decision which has a lot of detail about what happened to a linesman in Alabama when a homeowner generator energized some lines during an outage.
A safe and cheap way is to run a few outlets that are only fed by the generator. They never go to the panel.
Basically you’re doing the same thing as using all those extension cords. Except its run with proper 12/2 G Romex in the crawlspace. I’ve been giving this thought for my house. I only need 4 outlets. Two in the kitchen for the fridge and a counter top plug. One in the master bedroom for a lamp and tv. One in the living room for a lamp and tv, laptop.
It’s something I could easily do one Sat and never have to worry about those extension cords again. Power goes out, start the generator and plug the fridge, tv’s and lamps into the generator outlets.
So, it’s okay for you to break the law and place other people’s lives at risk, safeguarded only by your ability to not fuck up during a potentially stressful situation?
If the topic were different, I doubt you’d be taking this position.
The point of most of the safety considerations in electrical code is to ensure that systems are still safe even when things fail, mistakes are made, or people are stupid. Because things fail, mistakes are made, and people are stupid at times. It’s smart not to assume that you won’t make a stupid mistake, because almost all of us do sometimes.
Systems that are safe so long as everything works and nobody screws up aren’t really safe.
I think the fault is shared. The homeowner should not be backfeeding electricity. If he won’t install a proper switch and forgets to turn off the main breakers, he’s guilty of contributing to the death. The utility company should have procecdures to check for backfeed before working on the lines. It’s the responsiblity of the homeowner to ensure that the check on the part of the utility company is redundant, and redundancy saves lives.
Not sure what your point is. Line side conductors won’t be energized if a transfer switch is used. Line side conductors might be energized if a transfer switch is not used.
Almost if not all jurisdictions require a generator in use be isolated from service conductors.
What happens if power gets restored and your generator is plugged into the panel without a transfer switch? Would that burn out the homeowner’s generator?
I wouldn’t risk remembering to turn off the main breaker.