MEP-003A fuel tank (WTB)

[Ray70]

Sounds like the issue is that the shop is not running as a sub panel off the main panel, so therefore there is no connection between the 2 that can be disconnected from the grid, yet still keeping the 2 separate panels hooked together.
Instead of $8K worth of electrical work, you simply need another 803 for the house!
We always say... 1 is none , 2 is like 1 and once you have 3 you're just getting warmed up!

 

[glcaines]

I have 400 amp service coming into the house. I have two shops, one is above my attached garage, and the second one is a large one, two story, which we call the barn. Each of my shops has a separate panel which is powered off the main panel in the house via separate breakers, with cable underground, which I trenched myself. I found a 400 amp square-D manual transfer switch on Ebay, brand new for a really cheap price. I think I paid $180.00 for it. That thing is huge and heavy. I got permission from Blue Ridge Mountain EMC and the local building inspector to rewire the external panel my meter was located on. I didn't have to hire an electrician. EMC came out and killed the power to my house for two days while I did the re-wiring. I powered the house with my generator with a temporary connection while I did the wiring. EMC came out and inspected my work after I finished and didn't find any issues. When I lose power, which is fairly common, I simply throw the transfer switch and fire up the generator. It is then business as usual with no issues and no selecting which circuits I want backed up, including my shops. The buried line from the transfer switch is in conduit and ends with a pin & sleeve receptacle mounted on a wall near the generator. The line from the generator has a pin & sleeve plug on it. I previously used the 3 Phase from the generator to power my 3 Phase power tools, which I have a lot of. I have since put together a 7.5 Hp rotary phase converter to do this so I don't use the generator in 3 Phase much anymore. I'm not sure why you couldn't do the same thing at your place. The cost was minimal.
We also have a large cabin on the property with no generator backup. I intend to run another feed underground to the cabin, fed by a separate breaker in the panel in the house. As I mentioned previously, my MEP003A is enough to run everything without difficulty, including our Water Furnace geothermal heat pump. I have never had a single issue. I like the MEP003A because it is air cooled and extremely reliable. I got it at auction when it was returned from Iraq. It started it's life with the US Army in Japan and was sent to Iraq when the war started. I got it at a GL auction at Ft Jackson, SC, sight unseen, and got lucky. It also came with a complete set of tools and supplies.

 

[Ray70]

I think a possible solution for Clint would be to see if he could install a main disconnect switch between the service entrance and the split where the 150A and 200A individual feeds come from, such that he could disconnect from the grid, yet keep the 150 and 200A breakers closed.
This sounds like it would allow power fed into the Shop panel to backfeed into the House panel.
The issue will be how to do this with some functional Interlock system to keep it safe.
One possibility would be to use a matched pair of key operated interlocks where you use a single key that is retained in one interlock at a time to allow the new Generator "feed" breaker to only be closed ( with the key stuck in it) when the new "main disconnect" is locked in the open position ( lock position is the only way to remove the key and walk over the the generator breaker, unlock it and close it )

 

[clinto]

I'm not super knowledgaeable about AC wiring, so be patient if I have some of this wrong.

So, my power comes in off the street and goes through the meter. It then splits and goes through the two breakers (150A house and 200A shop). At that point, the 150A power goes in and travels to the breaker panel on the other side of the house, in the garage. The 200A power goes out of the service entrance as a 4-0 cable that's buried and runs about 150' to the shop, where it then enters the shop and feeds the shop breaker panel.

Pics:

I think the power comes in on the left, from the street. It then exits on the right and goes back to the shop.

The pex is for the fiber optic for the shop computer / internet and some of the junk still on the house is leftover from when I had cable. I'm going to clean all of this up this spring when I landscape this corner of the house.


Inside the panel. On the right, that's a surge protector.

My house as hit by lightning in 2025. I lost my desktop machine, monitor, server, UPS backup, router, surround sound in my office (speakers), surround sound in the living room (subwoofer and receiver), etc. This was while we were building the shop so I pestered the electricians to come up with any ideas for protecting the house against further strikes. What they came up with was:

• Surge protectors in both of the panels
• Good surge protectors in the house, including one where the internet signal enters the house
• Upgrading the grounds on both of the structures with larger wire than code requires. So both the house and shop have two 8' long ground rods and the wire attached to them is 4 or 6 ga (can't remember). Before it was either 6 or 8 ga.

They said anything beyond that wasn't really cost effective for a residence. It would have meant a ring of ground rods circling the house, stuff like that.

Will Ga. Power let me do this myself? I have plenty of friends who are competent to help me install a transfer switch. I just figured Ga. Power wouldn't turn the power off to my house without a permit or licensed electrician.

 

[Ray70]

So I assume the 150A service goes into the house through the rear of that enclosure and the 200S goes underground to the shop.

What I'm thinking would be a keyed interlock switch between the meter panel and the 150/200 breaker panel, allowing you to disconnect the service entrance meter from the 2 breaker panel. Then a breaker with matching keyed interlock in the shop's breaker panel ( assuming you will tie the generator into the shop )
As for legality, in my state the home owner is allowed to pull permits and perform all work themselves and the power company will disconnect the power upon request and reconnect once the town official has signed off on the final inspection. But I know not all stated allow home owners to perform electrical work so you should ask your town electrical inspector.

 

[glcaines]

I'm still not sure why you can't do what I did using a 4-pole 400-amp manual transfer switch located between the meter and house with the load for the house and shop coming off of the transfer switch. I also had a plaque engraved with instructions on how to start the generator and switch the transfer switch for my wife to use if I wasn't around when the power went out and I placed it on the front cover of the transfer switch. I did all of the wiring myself and working with that heavy cable was a royal pain.

 

[Guyfang]

This is big cable. Copper will whip your butt. ALU is much better. Still need to take a nap when you are done!! 60 meters of copper= 8,000 euro 4X240 square MM = 4X450 AWG. I recommend this to anyone having trouble sleeping.




This is 4X500 square MM = 4X1000 AWG. I once spent an 9 hour day, getting one of these babys, (120 meters long) through a wall, around two corners and hooked up to a D-Box.