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I am finishing out the second story of an essentially new garage. The plumber installed lines to an electric water heater in the attic, just above the bathroom. The plan is to finish all wiring for the upstairs, get the inspection, have the sheetrocking and trim done, and then call the plumber back to finalize hookups in the bathroom and kitchenette.
I am now looking over details for wiring the water heater. This is essentially new construction, since I can run wiring freely through the framing form the service box.
The unit is a 30 gallon 240V system with a black and red wires emerging from the top of the unit next to a green ground screw. The plan is to use two 30 amp breakers (GE) for the hot and red respectively, and then run the ground to the green screw. Now here comes the question: do I need a 10/2 or 10/3 Nymex cable to do this? If a 10/2 has a black, red and ground, then I believe I am ok using 10/2, since i only need the two alternating 120V hot lines and a signle ground. I believe a 10/3 is not needed since I don't need two hots, a neutral and a ground(?). I know 12/2 has 3 wires in it: hot, neutral, and ground, so I am assuming 10/2 has either a black, red, and ground, or black, white, and ground -- probably doesn't matter.
Here's my checklist:
1. First, nail a metal junction box to the joist just above (but not directly over) the water heater.
2. Run the Nymex cable from the service box to the attic (inside of course) across the roof joists to the junction box.
(there is 5/8" plywood covering the entire floor of the attic, but I don't think I want to run the cable across the attic floor -- unless it's enclosed in conduit -- doubt I want to do this)
3. At the service box, attach the red and black hots to two 30 AMP breakers in the service box.
4. At the junction box nailed into the attic joist(over the heater), secure the the ground wire with a screw threaded into the side of the box. Punch out a 1/2" knock out in the side of the junction box and run 10/2 flexible metal conduit to the cover plate of the water heater, secure the conduit to the plate. Connect the cables at the heater, and at the junction box.
5. Don't set the breakers to "On" until there's water in the heater.
6. For that matter, maybe run the wiring an don't make the final connections at the heater until water is in the heater(?).
Last, what will an inspector expect to see for the 10/2 that runs from the service box to the heater? Do I need metal conduit (pipe) when running accross the roof joists? (the light in the attic made code apparently and didn't need metal conduit -- its powered from a 14/2 simply running across the joists).
I am now looking over details for wiring the water heater. This is essentially new construction, since I can run wiring freely through the framing form the service box.
The unit is a 30 gallon 240V system with a black and red wires emerging from the top of the unit next to a green ground screw. The plan is to use two 30 amp breakers (GE) for the hot and red respectively, and then run the ground to the green screw. Now here comes the question: do I need a 10/2 or 10/3 Nymex cable to do this? If a 10/2 has a black, red and ground, then I believe I am ok using 10/2, since i only need the two alternating 120V hot lines and a signle ground. I believe a 10/3 is not needed since I don't need two hots, a neutral and a ground(?). I know 12/2 has 3 wires in it: hot, neutral, and ground, so I am assuming 10/2 has either a black, red, and ground, or black, white, and ground -- probably doesn't matter.
Here's my checklist:
1. First, nail a metal junction box to the joist just above (but not directly over) the water heater.
2. Run the Nymex cable from the service box to the attic (inside of course) across the roof joists to the junction box.
(there is 5/8" plywood covering the entire floor of the attic, but I don't think I want to run the cable across the attic floor -- unless it's enclosed in conduit -- doubt I want to do this)
3. At the service box, attach the red and black hots to two 30 AMP breakers in the service box.
4. At the junction box nailed into the attic joist(over the heater), secure the the ground wire with a screw threaded into the side of the box. Punch out a 1/2" knock out in the side of the junction box and run 10/2 flexible metal conduit to the cover plate of the water heater, secure the conduit to the plate. Connect the cables at the heater, and at the junction box.
5. Don't set the breakers to "On" until there's water in the heater.
6. For that matter, maybe run the wiring an don't make the final connections at the heater until water is in the heater(?).
Last, what will an inspector expect to see for the 10/2 that runs from the service box to the heater? Do I need metal conduit (pipe) when running accross the roof joists? (the light in the attic made code apparently and didn't need metal conduit -- its powered from a 14/2 simply running across the joists).
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