rlrobinhood
Member
- Location
- WY
- Occupation
- apprentice
Hi all,
I'm trying to understand the relationship between upgrading wire sizes to compensate for voltage drop and circuit protection. So, let me use an example:
A customer wants a 50 amp sub-panel 375' away from his main meter base. He will use this to power a 240 volt irrigation pump that requires 20 amp protection. Assuming an acceptable 5% voltage drop and 50 amp service at the subpanel, I believe the wire size should be #2 aluminum. The lugs on the sub-panel will accept this wire size. However, the 50-amp breaker (GE) at the main panel will not.
I believe there are two options to move forward on this:
1) Should the breaker on the main panel be up-sized to 100 amp to accept the upsized wire? I believe a 100 amp breaker is sized for #2 wire and the subpanel is rated at 100 amps.
2) Use a mechanical splice and splice the #2 aluminum wire to a short pigtail of #6 to allow for the connection to a 50-amp breaker.
I believe either of these is acceptable, what are your thoughts and preferences? Thanks in advance. I'm just struggling with the relationship between voltage drop and circuit protection. Many thanks!!
I'm trying to understand the relationship between upgrading wire sizes to compensate for voltage drop and circuit protection. So, let me use an example:
A customer wants a 50 amp sub-panel 375' away from his main meter base. He will use this to power a 240 volt irrigation pump that requires 20 amp protection. Assuming an acceptable 5% voltage drop and 50 amp service at the subpanel, I believe the wire size should be #2 aluminum. The lugs on the sub-panel will accept this wire size. However, the 50-amp breaker (GE) at the main panel will not.
I believe there are two options to move forward on this:
1) Should the breaker on the main panel be up-sized to 100 amp to accept the upsized wire? I believe a 100 amp breaker is sized for #2 wire and the subpanel is rated at 100 amps.
2) Use a mechanical splice and splice the #2 aluminum wire to a short pigtail of #6 to allow for the connection to a 50-amp breaker.
I believe either of these is acceptable, what are your thoughts and preferences? Thanks in advance. I'm just struggling with the relationship between voltage drop and circuit protection. Many thanks!!