I planned on buying any 240v generator and hooking it up to a double pull beaker to back feed panel.
Questions...
Are 240v gens 180 degrees out of phase?
Would a 240v water heater need a 180 degree shift to work?
Hmmmm. So if I’m back feeding my panel through a double pole breaker so both bars are hot, it doesn’t need to be 180 degrees out of phase?* All 240V AC devices (Including hot waters) are designed to run on a single sign wave.
* All 240V AC generators will provide a single sine wave of 240volts (RMS).
* Most 240V AC generators in the US will also provide Split phase 240v. (Split-phase 240 is what is used in US housholds)
With this, you get 3 wires: Two hot and one neutral (center tap).
If your hot water heater runs on 240V ac, any 240V generator with enough wattage will work. If you *also* want to run 120V appliances, you need to get a generator that provides 240V Split Phase. (I suspect that in the US, it might be hard to find a 240V generator that does not provide Split Phase)
- Between the two hot wires you will see a single sine wave of 240 volts.
- Between one of the hot lines and neutral you will see a single sign wave of 120V
- Between the other hot line and neutral you will see a single sign wave of 120V that is 180deg out of phase of the other 120V Hot-neutral line
If you have a split phase panel driving both 120V and 240V circuits you need to drive it with split phase 240.Hmmmm. So if I’m back feeding my panel through a double pole breaker so both bars are hot, it doesn’t need to be 180 degrees out of phase?
I’ve always thought hot bars were 180 out of phase.
And thanks again for reply.
I planned on buying any 240v generator and hooking it up to a double pull beaker to back feed panel.
Which is why I simply ordered this from Home Depo for $45:
Square D QO 150-225 Amp Indoor Load Center Generator Interlock Kit QOCGK2C - The Home Depot
Avoid the inconveniences that an unexpected power outage can cause with this QO Indoor Generator Interlock Kit. The Square D QO Cover Generator and QOM2 Frame Size Main Breaker Interlock Kit is used towww.homedepot.com
UL listed, legal, made by the manufacturer of my breaker panel.
Safe, so long as you don't remove the cover from the panel (thereby removing the interlock) and switch it. It is labeled warning not to do that.
When you use this, you can manually turn off excessive loads (such as electric central heat) if necessary.
One reason I went with this is it helps ensure several seconds off time before switchover, because I have some equipment that may not like the sudden shift in timing of AC sine wave which would occur with a fast transfer switch.
What does it do for mains input breaker? Video is a joke. Shows nothing. Says 'might eliminate need for'.
$45 for three little pieces of metal !
Best I can imagine is it prevents a generator backfeed breaker from getting turned on because of metal blocker interfering with main breaker ON position