Please help me think through an electrical problem

[Zach Dillinger]

Creekers,

My wife and I are purchasing a new home (our first, we've always rented a home from my parents). It has a tandem 2.5 garage, half of which will become my workshop. The garage is currently serviced by a small subpanel from the main breaker panel that powers a few outlets, overhead lights, and the garage door opener. I need to get more electricity to my garage. To further complicate matters, the existing dryer and range hookups are gas and the existing service to the home is only 100 amp. My wife wants a new glass-top range and an electric dryer and I'm not sure that the existing service will adequately power these new appliances.

I called the power company to get an estimate on updating my service to the main panel, but I was told that I would have to install a new 200 amp panel and rewire all the connections from the old panel to the new panel. I then asked about running a new 200 amp service to the detached garage with a seperate meter. I was told that I would be charged a $12.00 per month service fee for the new meter, plus I would pay 'general rate' for the power.

My question to you guys is this: would it make sense to bring the new service into the garage, pay the $12.00 a month fee and then subpanel back into the house for the new appliances, or would it be better to buy the 200 amp panel for the house, rewire it, and then subpanel the garage?

I'm leaning towards providing new service into the garage and subpanelling the house. The way I see it, I will have to subpanel no matter what and I would only subpanel 60 amp back into the house for the new appliances. It would save me on underground wire. Also, it seems that it would be much easier to do it this way so that I don't have to redo all the breaker connections at the existing panel.

Sorry for the long post, but what do you all think? What would you do if you were in my place?

Thanks,

Zach Dillinger

[Rob Russell]

I would:

Upgrade the service to the house from 100A to 200A.
Replace your main panelboard with a larger, 200A load center and tie all of the existing circuits into that new panelboard.
Run a subpanel out to the garage, 60A or 100A your choice.
You will probably need to replace the meter base as part of the upgrade - we did when we went from 100A to 200A because the 200A meter wouldn't fit on the 100A meter base.
I would not pay for a separate service to the garage.

Turning the house's existing 100A main panelboard into a subpanel could become a nightmare. In a subpanel, the neutral and equipment grounding conductors have to land on separate busses. In an old panelboard, you may not have long enough conductors inside the panelboard to make that easy. That would mean splicing/extending the conductor lengths and that's just going to look really messy in the panelboard.

If you ever decide to put central air in the house, you'll be glad that you have the extra ampacity of the 200A service at the house.

One thing will probably need to be done as part of the panel swap is upgrading the grounding electrode system. If the house does not have 2 ground rods, the electrician will probably need to bring that part of the installation up to code (if that's what your area of Michigan requires).

While replacing the main panelboard, I'd take the opportunity to install a Square D "QO" series load center - top quality.

[Prashun Patel]

I'd upgrade the main panel to 200A and subpanel the garage. The cable and installation will be a one-time fee, vs the $12/mo service fee for running a main panel to the garage.

Moving the breakers from one panel to a new panel is not a big deal. With the power off, it'll take a technician all but several minutes.

[Zach Dillinger]

Guys,

Thanks for your input. Taking the easy way out (i.e. new service to the garage) probably isn't the right way to go here. Looks like I'll be calling in a few favors with my electrician friends...

Thanks,

Zach

[Chris Friesen]

To further complicate matters, the existing dryer and range hookups are gas and the existing service to the home is only 100 amp. My wife wants a new glass-top range and an electric dryer and I'm not sure that the existing service will adequately power these new appliances.

Have you done a load calculation to determine whether or not you will need 200A service? My existing service is only 100A, and we have electric range and dryer, as well as AC. Furnace, garage unit heater, and water heater are gas.

I have a 40A circuit powering the garage subpanel. (Was originally going to make it bigger, then discovered the previous owner had left an unconnected #8 cable in the wall to the garage.)

40A is sufficient to run a 3HP saw and 1.5HP dust collector simultaneously, with lights on. Theoretically I could add another 1.5HP to that and still be okay. If I ever add a monster compressor or upgrade to a large cyclone (both of which could have 5HP motors), I'll have to upgrade the subpanel feeder.

[William Cummins]

Creekers,
My question to you guys is this: would it make sense to bring the new service into the garage, pay the $12.00 a month fee and then subpanel back into the house for the new appliances

If your in the US, and operating under NEC, codes you can NOT do this. You can not have 2 services into a building under "normal" circumstances (and the exceptions {Voltage, Phase, over 1200 amps} DO NOT apply in this case)



I'm leaning towards providing new service into the garage and subpanelling the house. Probably want to lean the other way as per the other posters advice :)

William...

[Matthew Dunne]

Congrats on the first house!

Off topic: Is your wife sure she wants an electric range? I so prefer cooking with gas. To each his, or her, own.

[Zach Dillinger]

If your in the US, and operating under NEC, codes you can NOT do this. You can not have 2 services into a building under "normal" circumstances (and the exceptions {Voltage, Phase, over 1200 amps} DO NOT apply in this case)

Probably want to lean the other way as per the other posters advice :)

William...


Thank you for the advice. I was only mentioning that option because the Service Engineer that I spoke with said it might be possible to do this. I will take the advice of the Creekers who posted here and simply upgrade the existing service.

[Zach Dillinger]

Have you done a load calculation to determine whether or not you will need 200A service? My existing service is only 100A, and we have electric range and dryer, as well as AC. Furnace, garage unit heater, and water heater are gas.

I have a 40A circuit powering the garage subpanel. (Was originally going to make it bigger, then discovered the previous owner had left an unconnected #8 cable in the wall to the garage.)

40A is sufficient to run a 3HP saw and 1.5HP dust collector simultaneously, with lights on. Theoretically I could add another 1.5HP to that and still be okay. If I ever add a monster compressor or upgrade to a large cyclone (both of which could have 5HP motors), I'll have to upgrade the subpanel feeder.

I haven't done a load calculation yet. 200 amp is what the power company supplies to new constructions in my area and I figured that I would have more excessive loads because of my woodworking. I'm moving into my first decent sized shop and I plan to upgrade some of my tools in the near future ( I really like the new Uni Saw...) so I figure I'll just do it once and get it over with.

[Zach Dillinger]

Congrats on the first house!

Off topic: Is your wife sure she wants an electric range? I so prefer cooking with gas. To each his, or her, own.

Thanks! April and I are very excited. And I'm quite sure she wants a new electric range.... she keeps ogling the glass tops at the Borg.