480-volt, three-phase, deadman leg

Status
Not open for further replies.
F

fishingfred

Member
Came across something I have never seen before, 480-volt three-phase service in an old industrial part of town. Service has three legs and ground, when checking voltage I got 480-volts between L1 &L2, L1 & L3, L2 & L3. L1 to ground 480-volts L3 to ground 480-volts
L2 to ground 1.3 volts, power company came out and said all is good, how could this be? Any one else ever see this? how can I be getting 480-v to ground on 2 legs/
 
fishingfred said:
Came across something I have never seen before, 480-volt three-phase service in an old industrial part of town. Service has three legs and ground, when checking voltage I got 480-volts between L1 &L2, L1 & L3, L2 & L3. L1 to ground 480-volts L3 to ground 480-volts
L2 to ground 1.3 volts, power company came out and said all is good, how could this be? Any one else ever see this? how can I be getting 480-v to ground on 2 legs/
Click to expand...
It looks like you have a corner grounded delta, often called a Grounded B phase system.

Remember ground is simply a reference point, therefore any one conductor can be grounded. This is why the NEC, in article 250 uses the term 'grounded' conductor and not 'neutral'.
 
Status
Not open for further replies.
Top