300A residential service

[goldstar]

I can't remember ever upgrading from a 100A to a 300A overhead residential service in my EC career. I've done several 400A services where I had to install CT cabinets and MBP's thereafter and that seemed fairly straight forward. So, I'm looking for some opinions on how you would proceed with this. Some of my EC colleagues have suggested the following :

• Install a 320A meter cabinet with double lugs on the load side. Install (2) 200A MB panels on the inside and feed each one separately in 2" PVC from the meter enclosure

This might be a bit difficult as the face of the residence has a stone finish. Punching (2) holes might prove to be a PITA

• Install a 320A meter cabinet with single lugs on the load side. Run the service conductors via PVC into a trough in the basement and install the (2) 200A MBP's out of that trough, tapping into the service conductors in the trough with Polaris bugs.

I've already checked with the POCO and a 300A service is permitted as long as the run is not longer that 120'. A mast is not required as the POA is high enough on the house.

Any opinions would be greatly appreciated. Thanks in advance.

 

[infinity]

Why two 200 amp panels if you only need a 300 amp service?

 

[goldstar]

It's more about having spare circuits for the future. I could just as well install (2) 150A MBP's (30/60's) as opposed to (2) 200A (40/80's). Chances are he'll never reach anywhere near 200A. I could just as well install this Sq D 54 circuit MB panel and make it easy on myself :

SQUARE D QO154M200P QO PLUG-ON NEUT LC N1 1PH MB 240 V 200A | Gordon Electric Supply, Inc.

SQUARE D QO154M200P QO PLUG-ON NEUT LC N1 1PH MB 240 V 200A

www.gordonelectricsupply.com

The house is about 4K sq/ft and the HO is a car collector (almost as intense as Jay Leno). He is tearing down the existing 2-car attached garage and building a 4-car attached garage with 4 hydraulic lifts so he can have 8 cars in the garage, AC/heating and God knows what else. The architect is calling for a 150 sub panel in the garage (overkill IMHO). Just looking for ideas with this. I'll probably run a 100A sub-panel to the garage.

 

[infinity]

I'm guessing that you're filing under the 2017 NEC? I didn't see you mention the disconnect on the outside. If money is no object why not use a meter main with 2-200 amp disconnects?

 

[goldstar]

I'm guessing that you're filing under the 2017 NEC? I didn't see you mention the disconnect on the outside. If money is no object why not use a meter main with 2-200 amp disconnects?

That's a good idea. I could do that as well.

 

[electrofelon]

IMO the cheapest and simplest is the two separate raceways to two seperate panels. Adding the wire away and connectors is going to increase cost a bit, personally I wouldn't care about how doing the second hole through the brick, but I have a core drill.

You could do sort of a combination of the two, run a single raceway with both sets in the one raceway and split off in a box or wire way to each panel without any taps or splices.

If you did disconnects outside, that's going to increase costs a lot but would allow you to put the inside panels anywhere you want which might be nice, not sure the layout.

 

[goldstar]

IMO the cheapest and simplest is the two separate raceways to two seperate panels. Adding the wire away and connectors is going to increase cost a bit, personally I wouldn't care about how doing the second hole through the brick, but I have a core drill.

You could do sort of a combination of the two, run a single raceway with both sets in the one raceway and split off in a box or wire way to each panel without any taps or splices.

If you did disconnects outside, that's going to increase costs a lot but would allow you to put the inside panels anywhere you want which might be nice, not sure the layout.

Thanks for your input. I appreciate it very much.

 

[electrofelon]

Thanks for your input. I appreciate it very much.

I always think about cost, but maybe it's not much of an issue here!

 

[SceneryDriver]

That's a good idea. I could do that as well.

I'm guessing that you're filing under the 2017 NEC? I didn't see you mention the disconnect on the outside. If money is no object why not use a meter main with 2-200 amp disconnects?

Heads up: I did the service on my house in NJ this spring, and PSEG specifically told me that they don't allow meter mains. They have no idea why; it was apparently written into their spec decades ago, and the guy who wrote it is long dead and gone, but no one wants to change it.


SceneryDriver

 

[infinity]

Heads up: I did the service on my house in NJ this spring, and PSEG specifically told me that they don't allow meter mains. They have no idea why; it was apparently written into their spec decades ago, and the guy who wrote it is long dead and gone, but no one wants to change it.

Seems silly that you cannot use a meter main when the NEC requires a disconnect on the outside of the dwelling. From the PSEG general guidelines for metering equipment it says "14. Combination meter pan and main units are not acceptable."

 

[shortcircuit2]

Around here it is months to get either a 320 meter socket or 320 metermain with 2x200amp breakers.

 

[4x4dually]

Forgive me if this is a dumb question, but aren't the 320A meters rated for 320A continuous/400A peak? Wouldn't that mean your feeders would need to be rated for 400A? Or are there actually 300A meters?

 

[Frank DuVal]

Here in Dominion territory we call it a 400 amp service, but it is a 320 amp meter. Meter base is provided by Dominion. I have always used two exits from this meterbase and fed two 200 amp panels. This service is common around here with heat pumps being the HVAC system of choice due to our weather.

Install a 320A meter cabinet with single lugs on the load side. Run the service conductors via PVC into a trough in the basement and install the (2) 200A MBP's out of that trough, tapping into the service conductors in the trough with Polaris bugs.

Can you just run 6 conductors in that PVC? (I have not checked conduit size required) Then each three wire set goes to its own panel. The exit hole knockouts on the provided meter bases are just 2 1/2" pipe size.

 

[electrofelon]

Forgive me if this is a dumb question, but aren't the 320A meters rated for 320A continuous/400A peak? Wouldn't that mean your feeders would need to be rated for 400A?

No, there's no requirement that feeders be sized to the maximum non-continuous rating of a meter socket.

 

[4x4dually]

No, there's no requirement that feeders be sized to the maximum non-continuous rating of a meter socket.

I guess I learn something everyday. I swear I read that on this forum just a few weeks ago.

 

[VirutalElectrician]

That's a good idea. I could do that as well.

Both Milbank and Siemens make nice 320A meter mains with dual 200a main breakers that are 2020 compliant.

 

[VirutalElectrician]

If he has a large garage coming, I would suggest one 200A panel to replace the existing one and the other 200A panel in the new garage.

 

[goldstar]

Thanks for all your replies and suggestions. I stopped by the house yesterday and found some new issues that I didn't see during my first walk-through, that are both comical and sad at the same time. Apparently, the person who lived in this house prior to the current owner was a self-made electrician/installer with a vivid imagination. Let me first describe the comedy.

• Service from the pole to the house is about 90-100' which is acceptable to the POCO. Sag in triplex is over 12'.
• After the POA the service conductors are in a 1 1/4" gal conduit that is strapped to the house, goes directly into the house and into the back of a tombstone meter enclosure
• Off the meter enclosure is a 100A FPE disconnect
• Off that disconnect is a 12 circuit FPE breaker panel
• Off that FPE panel there are (2) additional 12 circuit FPE panels
• Off one of those bsmt. FPE panels are (2) more FPE panels in the existing garage fed by a 30A feeder in BX
• Off one of the garage panels is a 30A welder receptacle in addition to whatever power the garage needs
• Also off one of the garage panels is an underground feeder to a barn that is about 100' away. That feeder looks like a piece of UF cable (looks like # 12)
• The barn was locked so I couldn't see but off that barn panel is another underground feeder to a greenhouse w/ propane heat
• Going back to the garage, there's another feeder going to a cabana and pool equipment but couldn't get in because it was locked
• Every receptacle in the house is a 2-prong receptacle including the ones in the kitchen

Looks like I'll be doing a lot of renovation work in this house over the next few years. Getting back to my original issue though, there isn't a lot of room on the outside where the service enters the house for me to install a 320A meter enclosure or to install one with (2) 200A disconnects. So, my thinking is that this house has been getting by all these years with a 100A service so, if I doubled the size to 200A I shouldn't have a problem. There's just enough room for a 200A meter enclosure. My intent is to have a 100A sub-panel in the new garage (when that;s built) to handle both the garage, barn and pool equipment.

I'll post more if I find any other weird things.

 

[Dennis Alwon]

Heads up: I did the service on my house in NJ this spring, and PSEG specifically told me that they don't allow meter mains. They have no idea why; it was apparently written into their spec decades ago, and the guy who wrote it is long dead and gone, but no one wants to change it.


SceneryDriver

I suspect it takes liability away from them when there is an issue at the home. Service guys only have to deal with meter and wont be responsible for lost screws etc on the meter mains.
It used to be that our power company would supply the meter base and they had parts to service them. I wonder if this is coming from that.