Steerpike

Looks very straight-forward, but .... aren't the two big fat black wires at the top the two 'phases' of the three-phase utility supply, whereas, the red/black at the bottom represent the single-phase from a generator? Is that kosher? Or - noticing the sticker 'LINE' above the 'left' wire, perhaps the left wire is one phase from the utility, while the right-hand wire is 'neutral'; that would make more sense, in terms of having the generator 'red' wire going to the 'LINE' feed, and the black wire going to the 'neutral' feed. But if that is the case, what happens to the 'other' phase coming into your home? Most homes have two phases coming in from the utility. Are you simply feeding the generator into one of the two phases, and then accepting that only 'half' of your home breakers are going to be 'life' in an outage?

Also - is this a simple example of a 'transfer switch'? Looks like it to me!

tht

That red and black wire look very thin, it can’t be a very high KW generator? I have a 100amp circuit and the wires are much thicker than that.

Nutek

It’s 10/4 but yeah, it needs replacing. 50 amp receptacle on the other end. Previous owner put it in.

we have never used it but we are looking at getting a new generator so I would want to swap that out at the same time. The rest of it seems ok.

Nutek

Single Phase. Those two thick wires carry 120V each You need another one for 3 phase.

[edit] Yeah.. Simple (old) transfer switch.

tht

The one I have to connect the 50amp 240v from the generator to the receptacle on the house is really thick, but I assume most of it is just to protect it.

It’s interesting what others said about not running AC. I was not sure ours would work, we have a gas stove and dryer, so when I have run this I did not really shut any thing off. I can definitely hear it work harder once the AC comes on, but it worked and managed to run that and everything else. I brought a smaller LPG unit for my other house, but it’s only 120v so I don’t think it can run my well pump… back to looking at solar and a power wall or 2 (assuming that can get through the night).

S Folinsky

Just upgraded the service on my house. Department of Water & Power did a “meter spot” and our 1938 power drop had to be relocated. So new main panel on north side of house with old panel on south side converted to a sub panel. I like to have basic knowledge of my house’s systems.

So, the power drop consists of the two black lines of 120 v each and the bare ground/neutral wire. I see that there appears to be a grounding cable coming out of the bottom. I presume that the conduit to the right hooks up to the meter.

This installation strikes me as a “Mickey Mouse” conversion of the house cutoff into a transfer switch. Betcha it ain’t legal.

Steerpike

I need to clarify / fess up that I was completely wrong above - typical houses do NOT get 'two phases' fed to them from the utility; they get two 120V lines, which are fed from a center-tapped winding on a transformer at/near the utility pole, which is fed by a single-phase of the utility source; correctly referred to by Nutek as 'split phase'.

I found this diagram online that really helped: Note, the 'flow' is from right to left (utility pole on the right, house on the left):


The question I still have for Nutek is what is the voltage generated by his generator; if his generator is 240V, then that makes sense - that is, the red and black wires coming into his 'transfer box' at the bottom are each 120V relative to ground, or 240V relative to each other. If the generator is only 120V (which I originally assumed when I replied above) then I don't understand how it could work. I've asked Nutek for more details by PM. Hopefully we can clarify here when resolved!

S Folinsky

Curiously, while we’ve been doing all the work on our house, LADWP updated the grid in our neighborhood. The linemen informed me that the high tension line before the transformers was 4200 volts.

Another thing I learned, and can be seen in Nutek’s box is that neutral and ground are bridged up until the main box. Sub panels are not bridged.

helwardman

Portable generators of that type are typically 240VAC.

Nutek

Passed inspection with no problems at all. Though I am looking to change it for a newer (and better) setup.

Nutek

Haven't purchased yet but yeah, 50amp 240VAC

ddsrph

The problem I see with the switch is the generator will
run directly to main panel with no breaker protection. The #10 wire can carry 30 amps but at the main panel it could be carrying the whole house. Also power companies are very particular about how long the feed wire is from meter to main panel. This wire is unfused and could burn/melt if it got shorted out.

Nutek

Correct, hence my desire to make changes once I figure out my best options. (Bear in mind this is currently (heh) unused)).

[Edit to add] The panel itself is directly behind the switch, on the other side of the wall.

ddsrph

I am interested in learning more about how modern transfer switches work. If convenient to do so seems like a lockout device would be the way to go unless a whole house generator is being installed.

Nutek

An Interlock Kit is really the way to go. It would take some considerable re-jigging on my (full) panel to do it though. Still... I may decide to go that way.