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FAQ Transfer Switches
This page lists frequently asked questions and answers about
manual transfer switches and transfer panels.
Click here for help in determining the best type for your application.
- Q: We live in rural Oklahoma and we have a well. We also do not have natural gas. I am particularly interested in how to connect items that don't have plugs such as the well or the furnace.
A: On our web site there are several configurations, B2, B3, etc. that are described with pictures and text. These should accomplish what you are asking. Your home should already have the electrical loads you mention connected to an electric panel. If a manual transfer switch such as one of our Reliance or Gen/Tran models is installed, all you would need to do during a power outage is plug a cable into the switch and generator, start the generator, and flip the toggle switches to energize the important pre-selected household circuits. For the largest switch, you can have up to ten 120V circuits powered from a generator. It is easy to install too. If you need more than ten circuits, an alternative is a transfer panel (sub-panel).
- Q: Thank you very much for your prompt delivery of the 30216 switch which I ordered from you the beginning of this week. I am very pleased with your prompt service. Could you please advise which of the connector cords I would need to connect the 30216 which will require a twist lock connector to the 220 volt outlet on my Coleman Maxa 5000 ER unit. It appears that the cord would need a male end on it. If such a cord is not available could you provide the necessary materials to build one. Please advise prices and availability.
A: Since your generator does not have a four pole receptacle there are several alternate ways to make the connection. The following alternative is based on a FAX from Coleman. Here is what we can provide or you can put together yourself. Use a four pole NEMA L1430R female connector for the switch end. When wiring, do not connect to the neutral in this connector. Just tie to the two hot positions and the ground position. According to Coleman, your generator 240V duplex outlet matches a NEMA 6-20P male 3 pole plug. In the plug on this end tie the two hot conductors and the ground. No connection is needed to the neutral on the 120V generator. In other words, use of only three conductors in cordset relies on the neutral to ground bond factory installed inside the generator and/or the neutral to ground bond in your home electrical panel. Some other generator models don't have this bond. We can provide this cordset fully assembled with the NEMA 6-20P and L1430R.
- Q: My residence has a Crouse Hinds 400A power panel. It is split with a 200A panel at the meter, and another 200A breaker that feeds a sub-panel inside the house, about 40 feet away. Both 200A breakers are in the same outside panel functioning as dual main breakers.
I am hooking up a 6500W generator that has 120 or 240+neutral (4 wire) wiring capability. With this panel there is really no way to safely just flip the mains and back feed for emergency use. Don't really want to back feed anyway. Therefore a Transfer Switch is needed.
The most of the important stuff like refrigerators (of course) are located on the sub-panel inside the house. This raises some questions for me.
In all cases the generator will be protected by it's own breaker. An yes I do understand you can't turn on everything anyway. My limitation is that I have an all electric house, water heater, heat pumps and water pump.
Therefore should I wire the system by ??
a) Placing a 400 amp transfer switch outside (where the generator will be) at the main panel and bypass everything. This requires me to call Edison and have an electrician shut down the power to rewire the meter section into the xfer switch, routing the output of the meter to the xfer switch then back. I cannot replace the meter section because it is a part of the outside panel and would definitely be too much work.
b) Wire two separate Gen/Tran type panels at each panel location, connecting some of the circuits, then connect both panels back to the generator.
One thing that I have noticed is the limitation of the reliance and Gen/Tran panels with 20 amp circuits. My water heater is breakered at 30A/220 and pulls 20A/220 when on. Should I configure a switch to feed it with 110V across the leads in a generator situation?
The only other important factor is the water pump, fused at 20A/220 and pulls 10A/220 after startup. The water pump and the refrigerator are at the top of the food chain and the water heater is last
This generator at 220v, 6500 watts, derated to 6,000 watts, will produce 27 amps at full load. Needless to say, the water heater at 4,400 watts running will not allow the water pump to start. The water heater is on the inside panel and the well pump is on the outside making manual selection of these circuits confusing and a hassle.
Do you know of any type of current sensing device that will relay drop out the water heater (or inversely let the water pump turn on) when the generator output has enough margin?
An my last question is how to safely protect the Generator. Do I simply connect 30A dual breakers? Am I correct in assuming the generator (Onan 6500,1800RPM) has some short term overload/surge capability?
What components do you carry that would provide a solution here? Thanking you in advance for your assistance.
A: It is obvious you have put a lot of thought into your options. Here are some ideas for you to consider:
1) Is the utility meter in the same panel as the two 200 amp breakers? If it is and the meter is bussed (rather than cabled) to the breakers, it might not be practical to wire a 400 amp transfer switch between the meter and the two breakers.
2) It would be fairly easy to install two Reliance or Gen/Tran switches, one at each 200 amp panel. But this would be rather cumbersome to use during an outage. You would have to read two sets of watt meters in two different locations (4 meters total) to manage your load total within the generator rating. And, like you noted, this will not address the large water heater load.
3) It appears that you should try to move the well pump and any other important circuits to the inside panel (assuming you can make space). Then you can just supply that one panel with generator backup in one of three ways: (a) with a 30 amp switch, or (b) replace this panel with a transfer panel, or (c) subfeed to a transfer panel. Here, (a) won't allow you to power the water heater but (b) & (c) will.
For option (b) the only difficulty with the transfer panel is its total capacity. It comes with interlocked utility and generator breakers. The largest utility breaker on some models is 100 amp. You will have to look at the number and size of the loads on your indoor 200 amp panel to see if a 100 amp panel is sufficient. Or, you might be able to move a couple non-essential circuits to the outside panel.
Option (a) is the most economical and easiest way to go if you can live without the hot water heater. I have the same issue in my home that is total electric. I have decided for now to go without the hot water heater on my backup generator. If a little hot water is required I can always heat some in the microwave or in a kettle on a Coleman stove. Not too convenient, but it uses about 2/3 less fuel than a gasoline generator would to heat the same amount of water. And, if you are preparing for a prolonged or widespread outage, conserving fuel may become a big concern. The other option would be to install a single-circuit 30 amp transfer switch dedicated only to the water heater. See the Reliance CSR series. Whenever you needed to heat water, just plug the generator cord into this switch until the tank is hot. Then move the cord back to your other switch.
As for your other questions:
... a current sensing device? yes, Gen/Tran just announced that they are introducing an automatic transfer switch with microprocessor control that WILL load shed less important circuits to keep the total within a generator's rating. But this device is presently at UL for testing and won't be available for sale until at least December 1999.
... short term overload capability? You mention two ratings for your generator: 6000 watt and 6500 watt. The higher number sounds like the short-time rating. To be sure, you might call Onan's technical support line with your particular model number and ask.
Hope these ideas are helpful. Of course, the more money you can invest, the better backup system you can get. I have tried to minimize costs in the above options. But if you have a lot of power outages, you would presumably want to invest more.
- Q: The switch instructions show the flex conduit only entering the bottom of the building panel. Can the Gen/Tran switch be mounted higher by connecting the flex conduit to the top of the building panel? This reduces the likelihood of children flipping the toggle switches and interrupting power at the most inconvenient times.
A: There is no problem using a knockout in the top of the panel rather than the bottom.
- Q: Gen/Tran transfer switches come with 18'' of cable. Can they be obtained with a longer cable, say 30 "or so? I have a crowded power center and it would be difficult to get by with 18".
A: The flex conduit length on the Gen/Tran switches is 18 inches. The lead length beyond the end of this conduit is another 28 to 34 inches. So, you should have enough to work with.
- For additional questions and answers on Gen/Tran products, go to the Gen/Tran Corp. web site by clicking here. For some other brand transfer switches click these links to their web sites: Reliance Controls, Ronk Electrical.