firestonesmith
New member
- Location
- Camas, WA
A year and a half ago, I put a 100-amp sub panel in our barn, 135 feet away from a service panel, supplied by two 1/0 aluminum URD and one #4 aluminum USE ground buried three feet deep, protected with a 90-amp breaker. The sales staff at the local Plumbing & Electric store advised me to use two leads and a ground of this gauge, and, thinking that it's just like running a regular 220V circuit, I agreed. But after installing it, I realized that their advice was wrong. I've isolated the neutral and ground bars in the sub panel and bonded the ground bar to the panel box.
The problem: The neutral bar is running on the #4 ground wire back to the service panel. I've seen this problem pop up in another thread but don't see my answer there. I wonder if this light neutral wire could work running off of a 50-amp breaker instead of a 90-amp?
The bonded ground bar is grounded independently to two 5/8" galv. ground rods eight feet deep, 8 feet apart, like a service panel.
Why is this configuration okay in a service panel but not in a separate-structure sub panel?
The problem: The neutral bar is running on the #4 ground wire back to the service panel. I've seen this problem pop up in another thread but don't see my answer there. I wonder if this light neutral wire could work running off of a 50-amp breaker instead of a 90-amp?
The bonded ground bar is grounded independently to two 5/8" galv. ground rods eight feet deep, 8 feet apart, like a service panel.
Why is this configuration okay in a service panel but not in a separate-structure sub panel?
