Parallel Mains?

[jeffg]

I had a new 400A service added to my property and I am in the midst of getting the meter box hung and wired to the main breaker panels. I am definitely not an electrician, but I feel confident that I can get everything wired up prior to the power company connecting services.

I went to a highly regarded electrical supply house today to get the conduit and things I would need for my project. We spent quite a bit of time drawing out the layout and the clerk selected the parts I needed.

At a high level what we are doing is bring service underground into a 400A meter base. The meter base is fitted with dual lugs on each leg. From the meter base I was given two identical 8 space 200A main breaker panels. The ideas that one panel will feed the future house, and the other panel will feed some local circuits and a 100A sub panel in the barn. The meter base and panels will be installed about 100' from the house and 50' from the future barn. Neither the house nor the barn have been built yet.

I dont understand the need for an entire panel just to feed the house 100' feet away. The house panel would just have a single breaker in it to feed the house.
Why couldn't I just wire the house side to a 200A disconnect and then do a panel in the house?

 

[Charlie K]

Your first problem is getting design and engineering help from a counter man at the supply house. I have been in the trade for 45 years and I know quite a few counter guys. They sell the product however they have probably never installed it. Let alone getting it to pass inspection. I see no reason why you needed 2 200 amp panels. A 200 amp fused service rated disconnect and 1 panel should suffice.

 

[brewchief]

What's the price difference between the panel and a simple disconnect? It may be very close and it does offer a few more options in the future, it would be very easy to add a generator interlock to the house panel and have a easy way to hook up a generator and keep it away from the house a bit to reduce noise.

Sent from my SM-T510 using Tapatalk

 

[jeffg]

What's the price difference between the panel and a simple disconnect? It may be very close and it does offer a few more options in the future, it would be very easy to add a generator interlock to the house panel and have a easy way to hook up a generator and keep it away from the house a bit to reduce noise.

Sent from my SM-T510 using Tapatalk

But wouldn't that mean that I would have to run each circuit to be powered by the generator all the way to the panel by the meter? Thats a 100' run for each circuit.

 

[brewchief]

But wouldn't that mean that I would have to run each circuit to be powered by the generator all the way to the panel by the meter? Thats a 100' run for each circuit.

No the breaker interlock allows you to feed the entire house panel not just a few circuits, you do have to use some discretion on what you operate but you have all the circuits available.

Sent from my SM-T510 using Tapatalk

 

[jeffg]

No the breaker interlock allows you to feed the entire house panel not just a few circuits, you do have to use some discretion on what you operate but you have all the circuits available.

Sent from my SM-T510 using Tapatalk

Wow, that's cool. All of the Generator kits I have seen required circuit by circuit connections. I will check it out.

I did some searching tonight and it looks like 200A disconnects are kind of hard to find and the ones I did find were much more expensive than my 200 main breaker panel. I guess I could always swap out the panel for a disconnect down the road if I found one. That would require that the Power Company cut power though I think.

 

[wyliesdiesels]

Wow, that's cool. All of the Generator kits I have seen required circuit by circuit connections. I will check it out.

I did some searching tonight and it looks like 200A disconnects are kind of hard to find and the ones I did find were much more expensive than my 200 main breaker panel. I guess I could always swap out the panel for a disconnect down the road if I found one. That would require that the Power Company cut power though I think.

youre thinking of a manual branch circuit transfer switch

an interlock is NOT a transfer switch. It simply prevents the main breaker and the generator breaker from being on at the same time.

 

[jblnut]

youre thinking of a manual branch circuit transfer switch

an interlock is NOT a transfer switch. It simply prevents the main breaker and the generator breaker from being on at the same time.

I have nothing to add as far as smarts goes but this is what we did out here ... Copied from a post in my gallery thread quite a while back


My electrical guy got the interlocks and generator cord installed and wired up today. He put a 50a breaker on the left panel for the barns and hayshed and and a 60a on the right for the pump house and human house.

I asked him to put the cord/plug in an old enclosure if he had one to protect it from the sun and he delivered. Gonna maybe fire the generator up this weekend to see if it all works.

The electrician was in and out in less than 3 hours and he did a few other things for me at the same time. I'm not sure how someone can not afford to spend the money to do something like this correctly.


This is what powers the whole works when the power goes out. I've used the whole setup a half dozen times and it's super easy to switch from the genny to line power and back again and it's all safe with no chance of power being fed into the line by accident.

 

[sberry]

I would rather have 200 to 1 panel, that's what those types of panels are for. So you can feed to other stuff. No reason for 2 and 400. Making power is a pain from that.

 

[wyliesdiesels]

I asked him to put the cord/plug in an old enclosure if he had one to protect it from the sun and he delivered. Gonna maybe fire the generator up this weekend to see if it all works.

the only issue i see here is cordage is not to be used as permanent wiring. It appears the cordage enters the panel through that disconnect enclosure he salvaged

 

[Bert_]

the only issue i see here is cordage is not to be used as permanent wiring. It appears the cordage enters the panel through that disconnect enclosure he salvaged

This is so not an issue. You pull the cord out to reach the generator. The short ****** or whatever he used between the boxes is not a problem.

Funny thing is the box was actually a transfer switch.

 

[Bert_]

Personally I would rather just have a single 400a transfer switch, on-off-auxillary, as the service equipment instead of all those panels and breakers. Ronk makes nice ones.

 

[jeffg]

I opened all the boxes and started laying stuff out. I have a couple of questions, and I think I have a couple of either missing or wrong parts.

In the meter base, does the power company usually supply the terminals for the end of their connections? In the attached meter base photo, you can see I was given two dual lug terminals and two single lug terminals. I get the dual lug terminals for the hot legs out of the meter, but I am confused about the single lug terminals. Either they were meant to go on the power company connector into the meter line terminals, or they were meant to go on the neutral bar. If they were meant to go on the neutral bar, shouldn't it be another dual lug to feed each of the panels? So do I buy another set of lugs for the neutral bar, or do I exchange the single lugs for a dual lug?

Also, since both of the breaker panels are essentially the first panel on their respective series, should both panels be bonded neutral to ground?

 

[wyliesdiesels]

whats the part number on the meter pan?

 

[jeffg]

The two panels are both Siemens PNW0816B1200TC.

 

[jeffg]

I went ahead and finished up the panel wiring today at home before I haul it over to the farm site. I still need to add the ground to each panel, but I will do that over there once I get the ground rods in. Thanks for all the help everyone.

 

[wyliesdiesels]

....

 

[wyliesdiesels]

The two panels are both Siemens PNW0816B1200TC.

whoops. I meant meter pan.

I was gonna do a google search and see if i can find a white paper

I opened all the boxes and started laying stuff out. I have a couple of questions, and I think I have a couple of either missing or wrong parts.

In the meter base, does the power company usually supply the terminals for the end of their connections? In the attached meter base photo, you can see I was given two dual lug terminals and two single lug terminals. I get the dual lug terminals for the hot legs out of the meter, but I am confused about the single lug terminals. Either they were meant to go on the power company connector into the meter line terminals, or they were meant to go on the neutral bar. If they were meant to go on the neutral bar, shouldn't it be another dual lug to feed each of the panels? So do I buy another set of lugs for the neutral bar, or do I exchange the single lugs for a dual lug?

Also, since both of the breaker panels are essentially the first panel on their respective series, should both panels be bonded neutral to ground?

The PoCo doesnt typically supply the connectors because they need to be listed for use on that particular pan. so it looks like you were shorted some parts.

a part number on the meter pan and a white paper could confirm this.

Also, both panels are main service panels so yes the neutral bars need to be bonded. looks like you have the green bonding screw still in the bar. just make sure its torqued to spec if it wasnt from the factory. sometimes they leave them loose in case the panel will be used as a subpanel and the bonding screw needs to be removed.

 

[jeffg]

whoops. I meant meter pan.

I was gonna do a google search and see if i can find a white paper

The meter base is a Milbank U1432-O.

I went back to the supply house and got one more single barrel lug and another dual barrel lug so that I could get everything hooked up and still have 3 empty connectors for the power company.

 

[jeffg]

Last question before I can let this thread die.

For the grounding of the two panels, is it allowable to share a ground wire? My plan was to run a 4AWG bare copper from the ground in one panel down two the two ground rods (>6' apart) and then back up to the second panel. This would give both panels a connection to the ground rods and I would only need one connection to each ground rod.

Panel - Ground Rod - Ground Rod - Panel

 

[wyliesdiesels]

Yeah that would work.