lowdown
01-26-2010, 12:34 AM
I just wrapped up a 100A/240V, sub panel install into my garage and thought this write up might be useful to someone attempting to do something similar. I plan on covering everything down to the nitty grit. I would not have tackled this project without a good friend of mine who is an electrician.
House: Single phase, 200A service. Main panel is a Cutler Hammer "CH" style panel.
Trenching:
3 years ago, my electrician buddy and I upgraded the service to my garage from a 20A/120V to a 40A/240V service. At the time, we trenched and buried two runs of PVC conduit; 1 run of 3/4" and 1 run of 1." We used the 3/4" for the 20A/120V service. We placed the 1" for a future, larger amperage service. 3 years later, I'm really glad we did that.
Trenchers are available from Sunbelt Rental, United Rental, Home Depot, etc.
Garage Electrical Demand:
-Welder #1: Max draw = ~45A @ 240V. Welder placed on dedicated
50A/240V circuit.
-Compressor: Max draw = ~12A @ 240V. Placed on dedicated 20A/240V
circuit.
-Future Drill Press: Max draw = ~10A @ 240V. Future dedicated 20A/240V
circuit.
-Welder #2: Max draw = ~20A @ 120V. Placed on dedicated 20A/240V
circuit.
-Electrical Hand Tools, Chop Saw, Parts Washer, etc..Max draw = ~20A/ 120V (each). Placed on dedicated 20A/120V circuit.
-Interior and Exterior Lighting: Placed on dedicated 15A/120V circuit.
The Total distance from house panel to garage panel is approximately 135 feet. When measuring yours, be very generous. Measure both horizontally and vertically; ie. up and down walls as well as along walls. For instance, I have to come up approximately 4' up/out of my house panel into my basement ceiling. From there, another 30' in the basement ceiling then another 4' to the junction box set on my foundation wall. Total run (just in the house) = 38 feet. I bought 45 feet of wire for just this run.
The remaining run starts at a 6"x6"x4" junction box placed on the interior of my foundation wall, penetrates my foundation wall, and continues through the 1" PVC conduit in my back yard, into my garage. This is approximately another 80 feet. I noted 90' to account for having to turn 90* down into the back yard, coming back up at the garage, the position of the new panel, and having something to tape to while pulling the wire. I purchased 270' of primary wire and 90' of ground wire for this run. This wire for this run was fed through the 1" PVC conduit I had trench for and buried about 3 years ago.
The overall run is essentially:
House panel -> Junction Box @ Foundation Wall -> Garage
Materials:
I purchased everything but the wire @ Lowes since their wire prices are ridiculous. In retrospect, I wish I had priced everthing through the place where I ended up getting the wire. Anyway..
Garage panel - Cutler Hammer "Renovation Main Breaker Load Center." It's a 100A main breaker load center (panel), "BR" type, with 20 spaces. For about $65.00 you get the panel, the main breaker and a handful of other breakers, not a bad deal especially considering you can return the breakers you don't/won't use. Be aware that there are both main lug and main breaker style panels. Main lug panels do not have a main breaker (like your house panel) but main breaker style panels do. "BR" type has to do with the load center and breaker type.
Breakers - Be aware of the difference between single pole (120V) and double/2 pole (240V) breakers. Cutler Hammer makes both both CH and BR style breakers for the two different types of panels. Square D, another manufacturer, has different lines of breakers for its Q.O. and Homelite panel types.
-My house panel is a Cutler Hammer "CH" panel so I purchased a Cutler Hammer CH type 2 pole 100A breaker; pricey @ about $50 for just the breaker.
-The garage sub panel is a BR type which included a BR type 2 pole 100A breaker, five single pole 20A breakers and one 2 pole 30A breaker. I also purchased: one 2 pole 20A breaker and a few single pole 15A breakers.
Wire - Determining what wire you use with has everything to do with the over all electrical demand, wire ampacity (how much amperage the wire can carry), distance, packaging and cost. This is where knowing an electrical is handy since they have the books and knowledge on wire to run safely as well as conform to code. I used the following:
House panel to junction box @ foundation wall:
#1 Aluminum S.E. (Service Entrance) cable. The cable I used includes three #1 (three 1 gauge conductors) and one bare #3 ground. 120V along one leg of #1, 120V along the second leg of #1, nuetral along the third leg of #1, and ground along the bare #3. It essentially looks like a huge piece of Romex since it's all encased in a grey plastc jacket.
Junction Box to garage panel:
Three #3 THHN copper conductors and one #8 THHN copper conductor. #3 is the proper sized copper wire to carry 100A at 90' while the #8 is the proper size for ground to use for the same application.
50A welder circuit: #6 THHN X 2 (conductors), #10 THHN x1 (ground)
All the other circuits were already run with 12-2 Romex (#12 x 2, and ground).
Other Materials
-Split Bolts: Split bolts are used to make splices, the ones I purchased are made from aluminum. The come in handful of different size ranges. I purchased four split bolts for #3 wire and one for
House: Single phase, 200A service. Main panel is a Cutler Hammer "CH" style panel.
Trenching:
3 years ago, my electrician buddy and I upgraded the service to my garage from a 20A/120V to a 40A/240V service. At the time, we trenched and buried two runs of PVC conduit; 1 run of 3/4" and 1 run of 1." We used the 3/4" for the 20A/120V service. We placed the 1" for a future, larger amperage service. 3 years later, I'm really glad we did that.
Trenchers are available from Sunbelt Rental, United Rental, Home Depot, etc.
Garage Electrical Demand:
-Welder #1: Max draw = ~45A @ 240V. Welder placed on dedicated
50A/240V circuit.
-Compressor: Max draw = ~12A @ 240V. Placed on dedicated 20A/240V
circuit.
-Future Drill Press: Max draw = ~10A @ 240V. Future dedicated 20A/240V
circuit.
-Welder #2: Max draw = ~20A @ 120V. Placed on dedicated 20A/240V
circuit.
-Electrical Hand Tools, Chop Saw, Parts Washer, etc..Max draw = ~20A/ 120V (each). Placed on dedicated 20A/120V circuit.
-Interior and Exterior Lighting: Placed on dedicated 15A/120V circuit.
The Total distance from house panel to garage panel is approximately 135 feet. When measuring yours, be very generous. Measure both horizontally and vertically; ie. up and down walls as well as along walls. For instance, I have to come up approximately 4' up/out of my house panel into my basement ceiling. From there, another 30' in the basement ceiling then another 4' to the junction box set on my foundation wall. Total run (just in the house) = 38 feet. I bought 45 feet of wire for just this run.
The remaining run starts at a 6"x6"x4" junction box placed on the interior of my foundation wall, penetrates my foundation wall, and continues through the 1" PVC conduit in my back yard, into my garage. This is approximately another 80 feet. I noted 90' to account for having to turn 90* down into the back yard, coming back up at the garage, the position of the new panel, and having something to tape to while pulling the wire. I purchased 270' of primary wire and 90' of ground wire for this run. This wire for this run was fed through the 1" PVC conduit I had trench for and buried about 3 years ago.
The overall run is essentially:
House panel -> Junction Box @ Foundation Wall -> Garage
Materials:
I purchased everything but the wire @ Lowes since their wire prices are ridiculous. In retrospect, I wish I had priced everthing through the place where I ended up getting the wire. Anyway..
Garage panel - Cutler Hammer "Renovation Main Breaker Load Center." It's a 100A main breaker load center (panel), "BR" type, with 20 spaces. For about $65.00 you get the panel, the main breaker and a handful of other breakers, not a bad deal especially considering you can return the breakers you don't/won't use. Be aware that there are both main lug and main breaker style panels. Main lug panels do not have a main breaker (like your house panel) but main breaker style panels do. "BR" type has to do with the load center and breaker type.
Breakers - Be aware of the difference between single pole (120V) and double/2 pole (240V) breakers. Cutler Hammer makes both both CH and BR style breakers for the two different types of panels. Square D, another manufacturer, has different lines of breakers for its Q.O. and Homelite panel types.
-My house panel is a Cutler Hammer "CH" panel so I purchased a Cutler Hammer CH type 2 pole 100A breaker; pricey @ about $50 for just the breaker.
-The garage sub panel is a BR type which included a BR type 2 pole 100A breaker, five single pole 20A breakers and one 2 pole 30A breaker. I also purchased: one 2 pole 20A breaker and a few single pole 15A breakers.
Wire - Determining what wire you use with has everything to do with the over all electrical demand, wire ampacity (how much amperage the wire can carry), distance, packaging and cost. This is where knowing an electrical is handy since they have the books and knowledge on wire to run safely as well as conform to code. I used the following:
House panel to junction box @ foundation wall:
#1 Aluminum S.E. (Service Entrance) cable. The cable I used includes three #1 (three 1 gauge conductors) and one bare #3 ground. 120V along one leg of #1, 120V along the second leg of #1, nuetral along the third leg of #1, and ground along the bare #3. It essentially looks like a huge piece of Romex since it's all encased in a grey plastc jacket.
Junction Box to garage panel:
Three #3 THHN copper conductors and one #8 THHN copper conductor. #3 is the proper sized copper wire to carry 100A at 90' while the #8 is the proper size for ground to use for the same application.
50A welder circuit: #6 THHN X 2 (conductors), #10 THHN x1 (ground)
All the other circuits were already run with 12-2 Romex (#12 x 2, and ground).
Other Materials
-Split Bolts: Split bolts are used to make splices, the ones I purchased are made from aluminum. The come in handful of different size ranges. I purchased four split bolts for #3 wire and one for