enireh
Senior Member
- Location
- Canyon Lake,TX
when grounds and neutrals are separated at sub panel there will still be continuity between them because they are not separated back at main panel. right?
Yes. As long as the main bonding jumper is in place there should always be continuity at any point in the system.
then what is the difference if they are not separated at sub panel? resistance?
The equipment grounding conductor is only supposed to carry current during a ground fault so tying it to the neutral in the sub would have it carrying current all the time and would be a parallel path as Trevor stated.then what is the difference if they are not separated at sub panel? resistance?
The equipment grounding conductor is only supposed to carry current during a ground fault so tying it to the neutral in the sub would have it carrying current all the time and would be a parallel path as Trevor stated.
And to add to what has been said - once you start to carry current on any conductor you have voltage drop. May not be much but it does increase as the current increases.
This can leave you with the equipment grounding conductor operating at a voltage above ground and that will increase shock hazards when touching equipment that is connected to the equipment grounding conductor.
So that equipment grounding conductor that remains isolated from neutral conductors all the way back to the main bonding jumper has very little to no voltage to earth/other grounded objects. The one that has been connected to current carrying neutrals along the way to the main bonding jumper is carrying neutral current and has a voltage rise to ground that is equal to the voltage drop in the current path. Voltage drop (voltage rise on the EGC) of 2 or 3 volts can go unnoticed pretty easily, but in the right circumstances is very noticeable. You will feel that in and around swimming pools or other similar areas.
The equipment grounding conductor is only supposed to carry current during a ground fault so tying it to the neutral in the sub would have it carrying current all the time and would be a parallel path as Trevor stated.
You need a complete circuit to light a light bulb and to trip a breaker.Say you have a main breaker only panel with no sub, the grounded and grounding conductors are tied together, how is the EGC not able to carry current? How is current being able to be carried on the grounded or grounding conductor any different in a main or sub panel? The main has a parallel path between the two conductors right?