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-   -   Panel Replacement/Upgrade 400 Amp (http://www.diychatroom.com/f18/panel-replacement-upgrade-400-amp-35105/)

AndrewF 01-04-2009 10:09 PM

Panel Replacement/Upgrade 400 Amp
 
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I pulled a permit a few months ago to do a panel swap (200amp) and replacement the ground mount meter base with a wall mount.

I haven't started the project yet for several reasons, but now that winter has arrived, I figure it is a good winter project.

The current panel is a push-o-matic panel and is a disaster. It buzzes and hums when things like the microwave or other appliances are on.

I contacted the local electric utility and asked about upgrading to 400 amp service. They said it would be no problem from a plant perspective. Everyone I have talked to suggested to upgrade to 400 amp service since the cost to do so now is minimal compared to me deciding to do it later.

Background
Main panel (200 amp)
Sub-panel (100 amp) new in basement

I built a 40'x68' barn/workshop and will be running 60-100 amp service to it in the spring.

Can I install a 400 amp dual tap meter socket and then split two 200 amp feeds to two 200 amp panels in the garage without having any exterior shutoffs? These two panels would be on the opposite wall of the meter and require runs less than 8'.

One panel would have all the existing wiring the old one does. The second panel would have the 100 sub-panel and the 100 amp panel to the barn. (Note the 100 amp sub-panel sees max loads of 80 amps when the backup electric heat is on)

Gigs 01-04-2009 10:13 PM

I'm not sure how you sleep at night with that thing in your house.

Speedy Petey 01-04-2009 10:15 PM

Sounds like a fine idea. What you are referring to is a 320/400 amp service.
Rated at 400 amps, but 320 amp continuous. The meter pan is actually a 320A meter pan and the POCO uses a regular plug-in meter.

AndrewF 01-04-2009 10:18 PM

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Here is a photo of the panel location in the garage. The old panel is on the right, the future new panel is on the left.

My thought is instead of moving all the circuits from the panel on the right to the panel on the left, is to just put a new panel in the location of the old and leave the panel on the left for the sub-panel to the basement (100 amp) and 100 amp to the barn.

What I want to avoid is having a bunch of clutter on the outside wall of the garage outside of the conduit to bring the underground service up to the meter box and then the two 200 amp feeds to the new panels.

InPhase277 01-04-2009 10:34 PM

I too would upgrade. Your plan seems ok, but check back in with questions. I personally like to have disconnects on the outside of the structure, but short back-to-back runs are fine.

Also, I want to say, you guys are really hard on old services! With a little TLC and some clean up and torquing, alot of old service panels can be made like new.

AndrewF 01-04-2009 11:09 PM

Quote:

Originally Posted by InPhase277 (Post 207090)
Also, I want to say, you guys are really hard on old services! With a little TLC and some clean up and torquing, alot of old service panels can be made like new.

Well, what started this all was my plan to put 100 amp service into my workshop and having to put 100 amp sub-panel in the basement for the 20KW backup heat. This push-o-matic panel is full, was overstuffed and it would cost around $100 for a 100 amp breaker alone.

The pedestal being ground mounted since 1977 and they have a tendency to rust out and collapse and with it missing the glass front plate to keep little hands and arms out of it...were a few of the reasons I decided to do a panel swap...from there the project just kept growing.

One of the things I hope to get rid of is that when the 5 ton heat pump kicks on, the house lights dont all dim! That annoys me.

nap 01-04-2009 11:31 PM

Quote:

Can I install a 400 amp dual tap meter socket and then split two 200 amp feeds to two 200 amp panels in the garage without having any exterior shutoffs? These two panels would be on the opposite wall of the meter and require runs less than 8'.
IF the panels are next to each other, this is legal. If they are not right next to each other (like you cannot have to take a step to reach the second panel), you will have to have a main disconnect somewhere.


Each panel has to have a main breaker in this type of install.

Now, you may run into a problem with the distance inside the building. It seems every inspector has his own allowances. Check with him before actually installing.

Oh, and you will have to get rid of that bench in front of the panels. You have to have 3 ft clear space in front of a panel and 30 inches or the width of the panel(s) (whichever is ggreater) side to side.

InPhase277 01-05-2009 12:02 AM

Andrew, I agree you should upgrade your service. My comment on old services was about how every question about an old service automatically turns into a "Rip it out" thread, but sometimes that isn't practical or affordable for some. There are often options other than "rip it out".

Quote:

Originally Posted by AndrewF (Post 207104)
One of the things I hope to get rid of is that when the 5 ton heat pump kicks on, the house lights dont all dim! That annoys me.

Bad news! You may not solve this by upgrading!:eek: This is usually due to voltage drop on the utility's conductors. So unless the power company runs extra large conductors to your new service (not likely), you will still have some dimming when the heat pump kicks in.

Speedy Petey 01-05-2009 07:48 AM

Quote:

Originally Posted by InPhase277 (Post 207127)
Bad news! You may not solve this by upgrading!:eek: This is usually due to voltage drop on the utility's conductors. So unless the power company runs extra large conductors to your new service (not likely), you will still have some dimming when the heat pump kicks in.

Ah yes. It is a very common misconception that a service upgrade will cure ailments such as that and also breakers tripping. It can be very hard trying to explain to a customer that the service size has no bearing on those things.
Sure, things like splitting up a double tapped breaker will help, but a service is not a cure-all for electrical problems in the house.

AndrewF 01-05-2009 10:34 AM

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I have a dedicated transformer for my house, buried extremely close to the house (IMHO). The transformer is fed 7500 volts from the main line from the road. The distance from the transformer to my meter will be approximately 60 feet. I had the electric companies engineer come out and make sure the transformer would support 400 amp service, it will. They will run new cable from the transformer to my meter socket, even if I only do 200 amp service. I can't find my notes, but I believe he said they'd run 000.

I had thought about running larger wire to the outdoor unit as well and instead of running it off of the garage panel (~90' run) to run it off of the 100 amp sub-panel in the basement, which would be a 40' run.

jamiedolan 01-05-2009 11:37 AM

Quote:

Originally Posted by AndrewF (Post 207287)
I have a dedicated transformer for my house, buried extremely close to the house (IMHO). The transformer is fed 7500 volts from the main line from the road. The distance from the transformer to my meter will be approximately 60 feet. I had the electric companies engineer come out and make sure the transformer would support 400 amp service, it will. They will run new cable from the transformer to my meter socket, even if I only do 200 amp service. I can't find my notes, but I believe he said they'd run 000.

I had thought about running larger wire to the outdoor unit as well and instead of running it off of the garage panel (~90' run) to run it off of the 100 amp sub-panel in the basement, which would be a 40' run.

3/0 in AL I am sure, which would be the same as 2/0 copper (I think that's the right conversion). Which really sounds a bit undersized to me for 200A for a 60' run. Service cables from the power co are sized differently and the NEC does not apply to them. So I don't know all the details.

What I do know if that often the connection from the transformer to your house is the connection that is to blame for voltage drop and is the reason behind much of the light flicker type problems. If it where my house, I'd be mounting a pedstal meter with a disconnect (so the service is fused right away) right there in the yard as close to that transformer as they would allow it. I hate seeing unfused cable, and most inspectors won't allow it to be run very far anyway, it's just too dangerous if someone ever hits it.

Then I would run 3/0 THHN (I would think about 4/0 if it was affordable to compensate for voltage drop) into the house in conduit from that pedstal meter / disconnect setup for 200A service.

Just some thoughts from me. I am sure Inphase or one of the other guys will correct me or add to this if I am mistaken on any of it.

Jamie

AndrewF 01-05-2009 01:02 PM

The county wont permit a pedestal meter like I have now, they want me to replace it, so does the electric company.

jamiedolan 01-05-2009 01:49 PM

Quote:

Originally Posted by AndrewF (Post 207369)
The county wont permit a pedestal meter like I have now, they want me to replace it, so does the electric company.

Ok, How about on the corner of the house that looks to be about 10' away from the transformer. Either on the side by the door or on the other side by where the gutter is? Is that only about 10'?

If you want the best chance possible of getting rid of or minimizing the light flicker from high amp start ups, then you want to get as close the power co feed (that transformer) as possible.

I can't tell exactly now from your first photo, but it kind of looks like you have expose cable run from your box up over your door then back down into your house, is that correct?

Jamie

AndrewF 01-05-2009 06:21 PM

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The existing panel and all wiring terminates in the garage, on the opposite side of the wall where i made the red meter marking in the photo. It would be cost prohibitive to move the panel anywhere else.

Any new wiring between the house and the garage has to go through conduit on the outside of the house as there is no other way (short of tearing walls apart) to get the feed to the basement.


Here are two more photos from a different angle.

Speedy Petey 01-05-2009 06:35 PM

Why is there a giant onion on your roof??? :eek:


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