Transfer Switch and Generator Install Questions

[Mr onetwo]

Would a Ronk 7103 switch be suitable to use as a manual generator transfer switch beside the 100 amp panel in my shop.It is fed from the pole outside and will also feed the houses 100 amp panel.I have a chance to buy a used switch for a decent price.Whole system will be fed with a 7.5 Kva diesel generator at some point.

 

[wyliesdiesels]

need a little more info

so you have a main service panel in your shop? and you want the transfer switch AFTER this panel or before it?
Do you want the shop to get generator power in addition to the house?

 

[Mr onetwo]

Thanks Wylie,
as it sits now the panels in the house and shop are main lug sub panels. If possible I would like to make the panel in the garage feed the house with a 90amp breaker. So from the meter disconnect to the transfer switch to panel in the shop which feeds shop and house.The meter disconnect is 200amp with 2 100 amp breakers.I don't want or need to run everything.Heat in the shop draws 2.4 fla.Biggest load in house is a Grunfos SQE 3/4 HP soft start pump 4.6fla, Z-line gas range 5.0fla and the Viessmann boiler system with ecm pumps that might draw 6 amps max...more like 250 watts total when running.Lights are all LED and heat pumps will not be included.

 

[Mr onetwo]

would it be possible to eliminate the 2-100 amp breaker/disconnects on the pole and run a 150amp sized wire into the shop to a new main breaker panel and transfer switch.Then just run off a 90 amp breaker and splice to the existing house wires out on the pole.That would give me a disconnect out on the pole and one in at the main panel inside the shop.Service entrance is a Midwest R281CB1LK

 

[wyliesdiesels]

Thanks Wylie,
as it sits now the panels in the house and shop are main lug sub panels.

well this is a code violation right off the bat, if you have more than 6 breaker handles in each panel...

If possible I would like to make the panel in the garage feed the house with a 90amp breaker. So from the meter disconnect to the transfer switch to panel in the shop which feeds shop and house. The meter disconnect is 200amp with 2 100 amp breakers. I don't want or need to run everything. Heat in the shop draws 2.4 fla. Biggest load in house is a Grunfos SQE 3/4 HP soft start pump 4.6fla, Z-line gas range 5.0fla and the Viessmann boiler system with ecm pumps that might draw 6 amps max...more like 250 watts total when running. Lights are all LED and heat pumps will not be included.

ok so you want to put the transfer switch ahead of the shop subpanel and then move the house feeder from the main service panel on the pole to the shop subpanel?

the hard part about that is you can only have the neutral bonded in one place. the transfer switch you have has a bonded neutral, which can be removed, but then you wont have a bonded neutral when you switch to generator power. so you need a transfer switch that switches the neutral...

 

[wyliesdiesels]

would it be possible to eliminate the 2-100 amp breaker/disconnects on the pole and run a 150amp sized wire into the shop to a new main breaker panel and transfer switch. Then just run off a 90 amp breaker and splice to the existing house wires out on the pole. That would give me a disconnect out on the pole and one in at the main panel inside the shop. Service entrance is a Midwest R281CB1LK

The transfer switch needs to be ahead of whatever panel you put in the shop. but that wont eliminate the bonding issue i brought up above.

have you done a load calc on the house and shop? i doubt you need more than 100a and if thats the case, there is no point in going through the trouble of running a larger feeder from the main service panel to the shop.

 

[Mr onetwo]

quote "well this is a code violation right off the bat, if you have more than 6 breaker handles in each panel..."

please elaborate....maybe my description is wrong.This setup was installed in 2009 and has been inspected multiple times.

 

[Mr onetwo]

I assume that a switch like this could be used with the listed neutral kit

 

[wyliesdiesels]

quote "well this is a code violation right off the bat, if you have more than 6 breaker handles in each panel..."

please elaborate....maybe my description is wrong. This setup was installed in 2009 and has been inspected multiple times.

if there are more than 6 breakers in a panel, it needs a main disconnect.

you said your subpanels are ML- main lug, meaning they dont have a disconnect....

just because it was inspected doesnt mean the inspector didnt miss the code violations

post some pics of your subpanels with the covers on and off...

 

[Mr onetwo]

Here's one of the panel in the house.I don't have a photo of the one in the shop but it is the same exact panel.I am confused...why would a panel like this be produced if it is illegal? I have wanted to get a bolt on QOM so there is a disconnect.I guess I'll see about picking one up. On another note I just picked up an MEP-802a surplus generator with a trailer in perfect shape(568 hours) for a good price.This will be the basis for my backup system.Is that switch I referenced above going to work for switching the neutral?

 

[Youngandfree]

Here's one of the panel in the house.I don't have a photo of the one in the shop but it is the same exact panel.I am confused...why would a panel like this be produced if it is illegal? I have wanted to get a bolt on QOM so there is a disconnect.I guess I'll see about picking one up. On another note I just picked up an MEP-802a surplus generator with a trailer in perfect shape(568 hours) for a good price.This will be the basis for my backup system.Is that switch I referenced above going to work for switching the neutral?

Codes vary in some locations and time frames. You don't happen to have a main breaker at the meter socket do you?

 

[Mr onetwo]

yes...see the photo in post #4

 

[wyliesdiesels]

Here's one of the panel in the house. I don't have a photo of the one in the shop but it is the same exact panel. I am confused...why would a panel like this be produced if it is illegal? I have wanted to get a bolt on QOM so there is a disconnect.I guess I'll see about picking one up. On another note I just picked up an MEP-802a surplus generator with a trailer in perfect shape(568 hours) for a good price.This will be the basis for my backup system.Is that switch I referenced above going to work for switching the neutral?

where did i say it was illegal?

a main lug panel with more than 6 breaker handles can be used when there is another panel ahead of it in the same building, such as a meter main.

you dont have that and therefore have violated code. that doesnt mean the panel is illegal.

 

[Mr onetwo]

sorry for the incorrect terminology Wylie.

I found a bolt on QOM100 breaker so that the panel in the house will be correct.

 

[Mr onetwo]

here is a schematic of what I would like to do. I have included all part numbers and as many details as I could think of.The generator will be hardwired and not movable except for service.Just let me know if it code worthy or you see something I missed.....many thanks!

 

[wyliesdiesels]

Looks good...

One question, do you want the shop powered by the generator?

Also, there should be 2 ground rods on your garage and house subpanels as well as at the generator...

 

[Mr onetwo]

I may finagle a way for just the heater in the garage to be on generator...it draws less than 3 amps. I am aware of the ground rods except on the generator.Is the ground rod necessary on the generator because it is hard wired?I thought because the neutral is switched that the generator becomes a stand alone power source and you do not use a ground rod in that instance.

 

[Mr onetwo]

there how's this? Also, I could always use a 30 amp cord and an inlet in the side of the transfer switch (in lieu of hard wiring) if it means I don't have to use a ground rod.

 

[wyliesdiesels]

I may finagle a way for just the heater in the garage to be on generator...it draws less than 3 amps. I am aware of the ground rods except on the generator.Is the ground rod necessary on the generator because it is hard wired?I thought because the neutral is switched that the generator becomes a stand alone power source and you do not use a ground rod in that instance.

Actually let me think on that one. Since youre switching the neutral, and the neutral bond is at the generator are you gonna run 4-wire to the transfer switch? If not then you wont have any ground rods tied between the generator and the transfer switch.

 

[Mr onetwo]

I can run a 4 wire cord from the generator to a wired inlet plug like this.

 

[Mr onetwo]

found in the code that if you use this type of inlet you don't need a disconnect

 

[Mr onetwo]

Wylie....I want you to know I really appreciate your advice on this project.That goes for anyone else who wants to chime in. There is only one set of ground rods on the property located at the meter on the pole.Maine was under the 2005 NEC at the time I believe so this was the way it was done.I want to do this right so I will put a set for the panel in the garage when I do this in the spring.The house is another kettle of fish and I am not going to address that here.My question pertains to the spacing of separate ground rod systems.Does the 6ft rule apply or can they be closer.I don't have much room along the garage wall because of 3 100 gallon propane tanks that are there.I will try to get a photo of that side of the garage to show how it is now and post it.

 

[wyliesdiesels]

IIRC ground rods at detached structures have been required for a lot longer than the 2005 code cycle

 

[Mr onetwo]

If there are other rods I don't know where they are.How far from the side of the garage would be ok? Can you elaborate on my other question about distancing between systems please?

 

[Mr onetwo]

anyone?

 

[Mr onetwo]

Actually let me think on that one. Since youre switching the neutral, and the neutral bond is at the generator are you gonna run 4-wire to the transfer switch? If not then you wont have any ground rods tied between the generator and the transfer switch.

Did you have a chance to think on it Wylie?

 

[mike93lx]

If there are other rods I don't know where they are.How far from the side of the garage would be ok? Can you elaborate on my other question about distancing between systems please?

They don't have to be a specific distance from the structure, but they have to be at least 6' apart, farther is actually better. Just need to get a continuous run of wire from the panel to the first rod

Even if they were additional, it wont hurt anything to install them

 

[Mr onetwo]

Bringing this thread back to life.I am thinking about substituting a split phase inverter/battery bank for the diesel generator previously discussed.EG4 equipment with solar panels in it's future perhaps.Are there any wiring concerns that are different than with a generator?A 40 amp 2 pole breaker feeds the inverter and it's 6000W output goes to the transfer switch.Should the ground and neutral be separate or combined on the inverter output since it is totally isolated by this transfer switch (3 pole)?

 

[Mr onetwo]

C'mon guys...a little help here

 

[wyliesdiesels]

I dont see how that will work

You have no way to isolate the inverter output from feeding the grid when the power is out. I dont see you specing an interlock on either breaker in the subpanel. If the 40a breaker is for solar feed, then you would be using a grid tie inverter which shits off when the grid goes down.

If youre using an off-grid inverter, then its not gonna shut off when theres loss of grid power and it will backfeed into the grid.

You wouldnt be able to do a dual feed like that with an interlock either… you would need a breaker from the inverter that is interlocked with the 150a main in that subpanel…

Most AHJs will make you put a disconnect on the output of the inverter and the output of the solar panels before they hit the inverter

 

[Mr onetwo]

The 40 amp feed is for battery charging only. If I shut off that breaker and flip the transfer switch how can I backfeed anything?This is an off-grid inverter that can be set up for grid down power backup only if you want.It has no way to feed the grid. The previous inverter has been updated and I changed the photos. "grid in" and "load" are separated in the wiring compartment with breakers.My other question would be if the neutral and ground gets bonded in the inverter since it is an isolated power source?

 

[TheEquineFencer]

I may finagle a way for just the heater in the garage to be on generator...it draws less than 3 amps. I am aware of the ground rods except on the generator.Is the ground rod necessary on the generator because it is hard wired?I thought because the neutral is switched that the generator becomes a stand alone power source and you do not use a ground rod in that instance.

I'm just thinking out loud. Can you just put this 3A load on a regular UPS? Then you could use solar power to charge the batteries when power is out? I have a 750W UPS I changed the batteries out and added roughly a 1200Ah 24V battery bank and it's charged by a 1200W array to run the computer system in my shop. It can work as stand alone system If I want.

 

[Mr onetwo]

Maybe....there is no solar input at this point.This is just going to be emergency power in lieu of a internal combustion generator.Space for the generator I was going to use(MEP-802a) and storing fuel has turned out to be an insurmountable problem.In the winter my garage is very cramped and I have added on twice already

 

[Mr onetwo]

The old adage "build it twice as big as you need" certainly applies

 

[TheEquineFencer]

After helping a friend with his "MIL-SPEC" generator, I hope it works for you, they "can" be a pain to get parts for.

 

[Mr onetwo]

not using generator....inverter/battery instead

 

[Mr onetwo]

I dont see how that will work

You have no way to isolate the inverter output from feeding the grid when the power is out. I dont see you specing an interlock on either breaker in the subpanel. If the 40a breaker is for solar feed, then you would be using a grid tie inverter which shits off when the grid goes down.

If youre using an off-grid inverter, then its not gonna shut off when theres loss of grid power and it will backfeed into the grid.

You wouldnt be able to do a dual feed like that with an interlock either… you would need a breaker from the inverter that is interlocked with the 150a main in that subpanel…

Most AHJs will make you put a disconnect on the output of the inverter and the output of the solar panels before they hit the inverter

I see your point about the interlock...I have one to put on the 150 amp subpanel in the garage.The inverter has a bypass mode to feed 50 amps of grid power to the load breaker. I think 50 amps is plenty to run what I would need during a power outage. This is a much cleaner way to do this.I don't think I need the transfer switch at all.

 

[dcg9381]

not using generator....inverter/battery instead

Seems like this use case is power back up. I believe that EG-4 product is relatively new. I have a bunch of their lower kW inverters and I run them in split phase. I understand you've got a grid feed on it - that purpose is to usually charge batteries, although it can be used (at least on mine) as pass-thru downstream.

How well that is going to work for a backup depends on your battery capacity... Looks like you have that covered with 3 batteries.
You cannot trust solar to power ****, you have to buffer to battery storage. Why? Because a single cloud can drop your power by 90%.

It is, to some degree, an ATS itself if you can isolate the load downstream. I think you've figured that out, interesting to loop it back to an interlock - it won't be automatic, but that should work.

Grounding is usually done within the inverter - EG-4 products (recently) have a config setting. I defer to Signature on it.

Watch EG-4's "idle draw" if you are going to depend on it. Idle draw can be quite high on these.

 

[Mr onetwo]

the battery is 14.3 Kwh , 280 Amp hours...it's a start.Idle draw is claimed to be <50 watts...we will see.Not going to use the pass thru at this point and 240V 40amp feed is for battery charging only.This inverter just launched yesterday...have been in conversations with EG4.

 

[dcg9381]

the battery is 14.3 Kwh , 280 Amp hours...it's a start.Idle draw is claimed to be <50 watts...we will see.Not going to use the pass thru at this point and 240V 40amp feed is for battery charging only.This inverter just launched yesterday...have been in conversations with EG4.

My advice: Don't be first with anything EG-4. Product review will be coming (diysolar) - let someone else vet this product. They were still changing hardware on mine and dealing with pesky little things like "how the hell do we ground it"...

I don't think you can disable pass-through on mine, you can "prefer" a power source, but I'm not sure you can totally disable it. So check that.

50W idle draw? That'd be one hell of an improvement over their 6.5s that idle draw around 250 watts.