I'm getting a high voltage on line1 to ground and Line3 to ground

kca

Member
Location
Philippines
Occupation
Electrical Engineer
I'm getting a rating of the following:

229 Volts on Line 1 to Ground
91V on Line 2 to Ground
230V on Line 3 to Ground

on a 240-volt, three-phase system, Y connection. Is this a problem?
 

kca

Member
Location
Philippines
Occupation
Electrical Engineer
Yes, sounds like a problem. Are these readings with the system unloaded?
the system is loaded, also when the load side ground tap to line side ground. then we energize the equipment the breaker will trip. is there a mis-connnection on the panel?

there's also a ct type on line 1 and line 3.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
The load side and line side ground wires are supposed to be connected together. If this causes the breaker to trip you have a strange problem.

Maybe you can sketch up what you have for us.

Is the breaker that is tripping on the primary side?
 

NewtonLaw

Senior Member
You mentioned this is a 240 Volt Wye system. Is the "Y" center point grounded? Or is this a three wire 240 Volt "Y"? The reason I ask is the voltages clearly indicate a problem. Most likely is Line #2 being all most grounded.

Would you please give a full list of voltage and current checks, along with a schematic of the wiring?
 

kwired

Electron manager
Location
NE Nebraska
Blown fuse on line two, or XO not bonded. Need more info such as line to line voltage.
My first thought, maybe not necessarily blown fuse but open circuit in the supply line on the one phase conductor. What voltage OP is reading is back feed from other lines through loads.
 
Top