Electrical help - Garage sub panel and backup generator conflicts

[dan1554]

Hi all, I just got my shop built but now need to start thinking about adding power. I have 200 amp service and want to run a 100a sub panel.

I ran in to a problem though. A previous owner installed a generac but it looks questionable. The original service lines are spliced in to much smaller wires that run to the automatic transfer switch. There is still the 200a breaker on the main panel.

My guess is that they thought since the electric baseboard was converted to propane hydronic they thought they could get away with smaller gauge wire. I don't think this will work for a 100a sub panel though.

My plan is to get a combo ats and panel (https://www.generac.com/residential...erator-transfer-switches/automatic/rxg42sha1/) so I don't have to run the 200a wires out to the current transfer switch.

Heres the main panel with the spliced mains:


and the transfer switch:



Am I on the right track here?

 

[The Cobbler]

I'm no electrician, and I hope I am wrong... but that looks scary as ****

 

[Chuckster in NJ]

My "professional advice" is to: Call a pro!

BTW! I am an experienced electrician (and retired electrical inspector) so please take my advice before you have a major problem.

 

[dan1554]

Ive been looking over the NEC with plans to get a permit, and we have an electrician acquaintance coming out next weekend. I'd like to be as educated as possible so I can come in to the conversation with some knowledge. It also helps me nerd out with some window shopping for new equipment.

 

[mm08822]

Yup, somebody screwed this up and very well too.
The ATS should have been a 200a service rated version.

I would get a new 200a xfer switch and make that the main panel. Turn your existing panel into a sub panel.

Ground rods get connected into the xfer sw. Bonding jumper also happens in xfer switch.

The "new" sub-panel gets fed with 4 conductors. Grd and neutral blocks are to be isolated from each other in sub.

The generac (Siemens) panel with built-in xfer switch is ok but limited with the number of backed up circuits it handles.

You have plenty of circuits and all wouldn't be backed up.

Please get rid of the drywall screw used as the bonding screw as you make this switch.

 

[Model A Fan]

Whoa , that's a really nasty rat's nest. I would recommend getting professional help. I like the idea of turning this one into a sub-panel and making a new primary panel.

 

[dan1554]

@mm08822 Thanks for the help. I too like the idea of keeping the current panel, but it could certainly use some clean up. I didn't even notice the drywall screw! Looking at whole-house transfer switches. The current transfer switch is 100A (not sure if its visible in the photo), again sitting between 200A service and a 200A breaker

 

[wyliesdiesels]

wow what a mess


looks like you have some ground wires that were cut bottom left corner in panel...

also may have some doubled up neutrals...

 

[mm08822]

I can't believe they cut the heater conductors off from the cables at the point of entry. Those could have been used for new circuits in the future. Only needed a box at the other end to make safe.

 

[dan1554]

Did some research on how to move forward and got a permit. Heres the plan:

• Run 3x #1 XHHW and 1x #6 ground in sched 40 conduit, to run up from the home panel in to the attic then down from the soffit in to a 8' long trench and up to the garage sub panel, 100amp
• Rewire the house panel and clean it up as much as possible. This includes temporarily disconnecting the generator (Ill get a new transfer switch and reconnect it at a later date). I also found a hot wire in the panel with damaged insulation and visible copper, to go along with that drywall screw.
• Ensure ground and neutral are separate in the house panel. The first point of disconnect is a breaker at the street meter and its bonded there. In addition to the drywall screw, there is a bare ground connected to the neutral side. Check neutral with ammeter to verify isolation.
• Mount a bar on the box and move the grounds there
• Remove unused breakers. I bought a new panel cover.

Hopefully I can get this all done while the kids are away at the grandparents. Any other suggestions 'while Im in there'?

 

[dan1554]

Praying to the permit gods

 

[mike93lx]

You need an expansion fitting in that or it's going to buckle at some point

Like this

 

[PCustoms]

You need an expansion fitting in that or it's going to buckle at some point

Like this

2 actually, one at each vertical.

 

[mike93lx]

2 actually, one at each vertical.

doesn't look like there is enough room for one on the left.

I'd definitely do one on the right but would probably skip the left

 

[dan1554]

Thank you both for the advice. I looked around and found a few horror stories of the conduit settling in the ground and ripping out the wall connection. I'll see if I can get expansions on both sides.

 

[dan1554]

Well just running the conduit is taking more time and money than I thought. So many trips to the hardware store.

Anyway, here's the attic routing. You can see it coming up through the soffit, and I need to do a little zig zag to the pipe sticking up through the drywall from the house panel. Any suggestions here to make the inspector happy? I know that technically it should have another expansion joint on the long run, would you add one?

 

[Innovate1]

Not sure which "long run" you are referring to. The one across the attic? Since it's mostly on the warm side of the insulation I would say not required but just my guess. You need two ground rods for the garage subpanel and can put them in the trench that's open. You are also going to need to make a proper connection between the conduit from the main panel to the horizontal run. If you use a large junction box that will allow later additions of other circuits without much trouble.

 

[dan1554]

@Innovate1 thanks for the feedback. Rough-in inspection should happen monday. Here's the final attic conduit. Don't mind the copious amounts of mouse **** - it probably adds to the r-value.

 

[dan1554]

First round with the panel. Disconnected the generator and cleaned up grounds and neutrals. Also removed all the old heater circuits. Really wishing they put the main breaker on the bottom. Those aluminum mains are a lot of wire to wrestle with.

Had to call it quits today and make sure the fridge stays cold. Still need to reorganize the breakers and tidy up the hots. The bottom left corner bothers me.

 

[mike93lx]

Looks a lot better

 

[mm08822]

Vacuum and brush out the bottom. Add KO seals to the unused knockouts to keep out the visitors.

Make sure any reds and the related blacks are on adjacent stubs (vertically) to each other

 

[dan1554]

Thank you both! Also forgot to mention that it's an older (1980s) system and there's no ground out to the meter/first disconnect. My understanding is that I either keep the house panel bonded or run a couple hundred feet of new line with a ground to the meter. Guess which option I'm choosing hopefully the inspector is understanding.

 

[mike93lx]

Is it a disconnect or just the meter? If it's just the meter, it should be three wire and bonded

 

[dan1554]

its a disconnect with 3 wires

 

[wyliesdiesels]

As long as theres no parallel metallic pathways, its code permissive since it was installed pre-2008 code cycle

 

[dan1554]

Passed the rough-in. I asked the inspector to take a quick glance at the panel (after cleaning and adding knock out covers re: @mm08822) and he said there was nothing obvious that he'd fail it over. Said it looked like I did my homework.

Thanks again guys for the help, this place is a great resource thanks to you. Time to start pushing some wire.

 

[mike93lx]

Passed the rough-in. I asked the inspector to take a quick glance at the panel (after cleaning and adding knock out covers re: @mm08822) and he said there was nothing obvious that he'd fail it over. Said it looked like I did my homework.

Thanks again guys for the help, this place is a great resource thanks to you. Time to start pushing some wire.

Glad it worked well and thanks for listening to advice. That doesn't always happen