200 amp service change

J

Jimmy7

Senior Member
Location
Boston, MA
Occupation
Electrician
I have a customer who wants to change their above ground 200 amp service in their single family home. The dryer and the range are both currently three wire. The panel is located in a finished basement that has sheetrock ceilings. The dryer and range are located on the first floor, so trying change them to four wires would be difficult. Is there a way in which I can keep these appliances three wire, change the service, and satisfy articles like 230.85?
I’m in MA and we’re currently in the 2023 code.
 
infinity said:
IMO no. The upgraded branch circuits would be required.
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I would have thought that NJ rehab code would have allowed the 3-wire to stay. Here, if we aren't opening walls, ceilings, etc. we can keep the existing. Changing the service would have no effect on branch circuit wiring.
 
If the 2023 code applies, and the circuits in question originate in the service equipment, the provisions of 250.140(B) many permit the existing 3 wire branch circuits to remain.

If the new outside disconnect is marked "EMERGENCY DISCONNECT, NOT SERVICE EQUIPMENT" you can have the service equipment inside and use the provisions of 250.140(B), assuming that the new service equipment is in the same location as the previous service equipment. If the dryer and range circuits would have to be extended of if they are supplied by a sub-panel, you can't use 250.140(B).
 
Little Bill said:
I would have thought that NJ rehab code would have allowed the 3-wire to stay. Here, if we aren't opening walls, ceilings, etc. we can keep the existing. Changing the service would have no effect on branch circuit wiring.
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He said he's in Massachusetts. :giggle:

As Don stated if the new panel is the still the service then nothing has to change even with the EM disconnect on the outside.
 
Jimmy7 said:
I have a customer who wants to change their above ground 200 amp service in their single family home. The dryer and the range are both currently three wire. The panel is located in a finished basement that has sheetrock ceilings. The dryer and range are located on the first floor, so trying change them to four wires would be difficult. Is there a way in which I can keep these appliances three wire, change the service, and satisfy articles like 230.85?
I’m in MA and we’re currently in the 2023 code.
Click to expand...
Hi, this is actually a very common issue when converting from a 3-wire to a 4-wire setup. The 230.85 reference is about the location of the emergency disconnect, but the sections that really matter for your situation are NEC 250.140 and 406.4(D), which address existing circuits and grounding requirements.

If the inspector requires a proper equipment ground, one option is to run a separate equipment grounding conductor (EGC) from the panel to the appliance location. This still involves pulling wire, but in some cases it’s easier than replacing the entire 3-wire cable, and it may result in less drywall disruption.

I’d recommend flagging this upfront with your customer, if the AHJ doesn’t allow it, portions of the ceiling may need to be opened and repaired. It’s best to factor that potential cost and impact into the project from the start. Hopefully this helps clarify the options.
 
I wonder if some inspectors might allow the old 3 wire dryer/range to bypass the old panel, now sub-panel, and get extended to the new main panel if the disruption to the house is a lot less?
 
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