The question I have is to whether or not the location that I am inspecting has adequate power. The facility is a single story, multi-room berthing (it is on a military installation in So Cal), somewhat like a motel. My command has been tasked with renovating two of the rooms. Upon inspection, the building is supplied by 120/208Y instead of single phase 120/240 (not sure why since there are no 3-phase loads). The rooms that we are renovating require a new sub panel which is how this issue arose. My question is, looking at ANSI C84.1, if you follow the 95% to 105% rule, this will not be acceptable for the 240V dryer and range being installed. If you follow the 87% to 106% it is okay. I think they NEED to install a new poletop transformer to provide this building with 120/240, but not sure if the HAVE to. Any help would be greatly appreciated.
120/208Y connected to residential
- Thread starter cuat_420
- Start date
- Status
- Location
- Massachusetts
208Y/120 3 phase services are common in multi unit dwellings, the main gear will be three phase but each unit will be single phase
Unit 1 'A & B'
Unit 2 'B & C'
Unit 3 'A & C'
and on it goes, this is good for the power company for load balancing.
As far as your dryer and ranges look at the label, I bet you find they are listed for 240 or 208 with different KW values for each voltage.
The units are designed for 208 use but the range will not boil water as quick as it would with 240.
Unit 1 'A & B'
Unit 2 'B & C'
Unit 3 'A & C'
and on it goes, this is good for the power company for load balancing.
As far as your dryer and ranges look at the label, I bet you find they are listed for 240 or 208 with different KW values for each voltage.
The units are designed for 208 use but the range will not boil water as quick as it would with 240.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Cuat, welcome to the zoo! :smile:
The reason the appliances are okay on 120/208v is because the 120v portions of a dryer, for example, are connected from L1 to the neutral. Only the heating element uses L2, and, as Bob stated, its power will simply vary with the L-L voltage.
If you ever get a service call about a dryer that runs, but doesn't heat, tell them not to buy a new dryer until you check for a missing line.
The reason the appliances are okay on 120/208v is because the 120v portions of a dryer, for example, are connected from L1 to the neutral. Only the heating element uses L2, and, as Bob stated, its power will simply vary with the L-L voltage.
If you ever get a service call about a dryer that runs, but doesn't heat, tell them not to buy a new dryer until you check for a missing line.
Thanks for the responses!! So the appliances should be okay (I can't check them because they have not been purchased...you know how the government is...lol). As far as splitting the phases between the units; that would make perfect sense....unfortunately, the group that did the rehab in the other units in this building installed 3-phase panels as sub panels also...I have no idea why. My problem now is the only panel available is a single phase 120/240V (without waiting forever for the government to procure a different one). If we use this panel it is going to leave a large imbalance at the main panel (I doubt anyone has ever balanced the main panel anyway), which is obviously a bad thing. Is there any way around this other than installing a 3-phase panel? Thanks a gain for all the quick responses.
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