Hi,
wondering if the experts here could check my sub-panel design before the inspector arrives tomorrow.
project is an outdoor 100A sub panel about 50 feet away from my meter socket (combo) panel, fed by 100A breaker in the meter socket panel. The sub panel is mounted onto an exterior wall of the same house as is the meter socket combo panel. The primary (and immediate) purpose of the sub panel is to provide 50A GFI protected service to a hot tub.
At the main panel (outdoor meter socket combination panel).
1. Neutral and ground are bonded in the main meter panel
2. #4 copper ground wire from main meter panel to pair of ground rods spaced 6 feet apart. Bond the existing Ufer ground #6 wire to the #4 wire. This may be overkill, but the Ufer ground connection looks questionable and I don't want the inspector to question anything.
3. main meter socket panel has a 100A breaker for the branch going to sub panel
4. Exit meter socket panel with 2" conduit sched 80 above ground. the branch to the sub panel is: 0-0-2 AL wire plus #4 copper ground wire from main meter panel to sub panel ground. 50 feet total wire length. AWG 0 is larger than necessary, but the 0-0-2 is available locally cheaper than #1AWG singles.
5. Conduit buried 18" below grade (that is local code). Sched 40 for underground sections.
at the Subpanel:
6. reduce to 1 1/4" sched 80 to come above ground for connection to subpanel (largest knock-out). enter sub panel bottom with male adapter and retaining ring.
5. #4 ground wire from the meter panel goes to sub panel equipment ground. no bonding to neutral in the sub panel.
6. 20A and 30A GFI breakers in the sub panel:
20A circuit is a pair of #12 wires (for the spa heater)
30A circuit is three #10s (two 120V circuits for the pumps)
#10 ground wire from sub panel to spa equipment ground
7. exit side of the sub panel with 1" grey PVC; attach to 1" LB conduit body (to assist making a sharper turn). underground to spa.
questions:
1. is my grounding plan (at the meter socket) a good idea or not
2. Can the spa equipment ground wire be #10 even though #4 wire goes back to the meter socket panel
3. Is #2 AL "reduced neutral" ok. The maximum possible unbalanced load for the panel itself is 80A assuming 20A dedicated to the spa heater and everything else is wired without paying attention to balance
In reality, The spa pumps (on the 30A circuit) will be wired for opposite poles. up to 50A is available for other things (unused right now), such as outdoor lighting, fountain, etc, etc.
wondering if the experts here could check my sub-panel design before the inspector arrives tomorrow.
project is an outdoor 100A sub panel about 50 feet away from my meter socket (combo) panel, fed by 100A breaker in the meter socket panel. The sub panel is mounted onto an exterior wall of the same house as is the meter socket combo panel. The primary (and immediate) purpose of the sub panel is to provide 50A GFI protected service to a hot tub.
At the main panel (outdoor meter socket combination panel).
1. Neutral and ground are bonded in the main meter panel
2. #4 copper ground wire from main meter panel to pair of ground rods spaced 6 feet apart. Bond the existing Ufer ground #6 wire to the #4 wire. This may be overkill, but the Ufer ground connection looks questionable and I don't want the inspector to question anything.
3. main meter socket panel has a 100A breaker for the branch going to sub panel
4. Exit meter socket panel with 2" conduit sched 80 above ground. the branch to the sub panel is: 0-0-2 AL wire plus #4 copper ground wire from main meter panel to sub panel ground. 50 feet total wire length. AWG 0 is larger than necessary, but the 0-0-2 is available locally cheaper than #1AWG singles.
5. Conduit buried 18" below grade (that is local code). Sched 40 for underground sections.
at the Subpanel:
6. reduce to 1 1/4" sched 80 to come above ground for connection to subpanel (largest knock-out). enter sub panel bottom with male adapter and retaining ring.
5. #4 ground wire from the meter panel goes to sub panel equipment ground. no bonding to neutral in the sub panel.
6. 20A and 30A GFI breakers in the sub panel:
20A circuit is a pair of #12 wires (for the spa heater)
30A circuit is three #10s (two 120V circuits for the pumps)
#10 ground wire from sub panel to spa equipment ground
7. exit side of the sub panel with 1" grey PVC; attach to 1" LB conduit body (to assist making a sharper turn). underground to spa.
questions:
1. is my grounding plan (at the meter socket) a good idea or not
2. Can the spa equipment ground wire be #10 even though #4 wire goes back to the meter socket panel
3. Is #2 AL "reduced neutral" ok. The maximum possible unbalanced load for the panel itself is 80A assuming 20A dedicated to the spa heater and everything else is wired without paying attention to balance
In reality, The spa pumps (on the 30A circuit) will be wired for opposite poles. up to 50A is available for other things (unused right now), such as outdoor lighting, fountain, etc, etc.