aavgerinos
Member
I’ve got two electrical projects for our house and wanted to run my plans by you guys to make sure I’m not missing anything serious. I’ve spent the last few hours searching this site as well as consulting a book I picked up a few months back (Practical Electrical Wiring, 20th Edition). I’ve learned all sorts of acronyms like NM-B, MC, BX, THHN, EMT, and FMC. Fun stuff.
The first project is adding an exhaust fan to a bathroom and the second is adding lighting and other circuits to the garage.
Background info: San Diego house built in 1961. When we purchased almost 3 years ago we had the main panel upgraded to 200A as well as had a couple of circuits added. If I recall correctly the original setup was like 100A and 2 or 3 circuits for the entire house. GFCI installed on all outlets since the original wiring didn’t have a ground (save for a couple of spots in the kitchen).
The first project, the bathroom, I think I’ve got a pretty good handle on. The current setup is switch to an overhead fixture. Behind the switch it looks like a pair of 2 wire cloth braided cables were run. The switch breaks the connection of the black (hot?) wire and the white (neutral?) is spliced with a wire nut.
My plan is to:
* Go up into the attic and run a length of 14/2 NM-B cable from the switch box to the overhead fixture. Approximately 15 feet.
* Replace the single switch with a duplex switch
* Use a short length of black 14AWG THHN wire to connect the original hot splice joint to the secondary switch
* Connect the primary switch as original
* Connect the white Romex wire to the original neutral splice joint.
* Connect the black Romex wire to downstream end of the secondary switch
* Wire exhaust fan and light as indicated in instructions.
Sound about right? Since I’ve got no ground, I’m assuming I just leave it hanging and leave the safety duties up to the GFCI located upstream.
The garage will be a little more involved. The previous owners had converted the garage into a “livable” area. I’ve since removed the carpeting, and false ceiling, but the walls are finished with drywall and mud. The wall that shares a wall with the house is stucco (I think this was original). In addition they added electrical outlets behind the drywall, but it’s all off the living room circuit.
I plan to leave the original wiring in place but I want to add:
* 1 20A 120V circuit for tools
* 1 240V circuit (single phase, amperage unknown)
* 1 20A circuit for lighting and other uses (drop light, etc.). Lighting will be handled by 2 switches.
Lighting
I’ve been gifted 7 dual bulb 4 ft T12 fixtures. Best I can tell, with all of them running, this will draw about 4.7A. If I didn’t have anything else plugged in, a 15A circuit would probably be fine. However, I plan to install outlets at each lamp so I can replace them when the ballasts **** out. As such, going with 20A means I have another circuit to use in the garage for tools and stuff.
The panel is located at one corner of the garage and I want to put the light switch at the opposite corner (near the door leading into the house). It is my understand that I could simply run the 12/2 Romex along the rafters and joists, along the perimeter of the garage, and then down the wall to the surface mounted electrical box. However, I’d like to protect the exposed vertical cable that will run from the joists to the box (approximately 5 feet).
Based on what I’ve read running Romex inside EMT conduit to a metal box is allowed for short sections according to the NEC. Some city codes don’t allow this. There is concern of overheating due to the extra level of insulation and of course everything needs to be grounded properly. However, for a length this short, I can’t really see this being a problem. And besides, how else protect this short section of cable? It would seem silly and wasteful to run Romex to an overhead box and then run armored cable or THHN inside EMT for just a few feet to another box. What do you think? I understand I also need to install a bushing or insulator on the exposed end of the conduit so as not to cut the wiring.
This box will have 1 duplex receptacle, and either 2 single switches, or 1 duplex switch. Out of this box I will run 2 Romex lines up into the rafters to handle the lighting. So that means I want to run 3 12/2 Romex cables into this box. At each termination point I’ll have one of those blue plastic outlet boxes nailed to a rafter. After I install the outlets I plan to cover up the exposed rafters, insulation, and wiring with some of that reflective foil stuff you see in industrial applications.
What size EMT conduit do you suggest? 3/4”? 1”?
Is there a smarter way of doing this?
I picked a metal box mostly because it looks professional. Grey PVC would work as well, right?
How would I attach the metal box to the stucco? Or is it better to find the studs and attach there?
Tool Power
The garage is small, and I don’t own a lot of power tools. Besides the preexisting shared line, how many additional 120V circuits are really needed? It seems to me I could probably do just fine with 1 20A circuit to power most stuff. I don’t have room for a drill press, table saw, or lathe and I can’t imagine using more than 1 high amperage tool at a time. For the additional 120V circuit, I’ll probably have 1 or 2 outlets along the side wall and 3 or 4 outlets along the back wall. Much like the lighting, I’m thinking metal boxes with short sections of EMT conduit to keep things nice and tidy along the visible portions of the walls.
I also want to add a 240V circuit. Eventually I’d like to buy a small welder and best I can tell they usually draw less than 25A according to the manuals (looking at Miller and Lincoln brands). A large air compressor draws less than 15A and it’s unlikely I’ll be running them at the same time.
For the plugs, it appears that 6-50 is the standard for welders so I’ll probably use that at all the 240V outlets. The 6-50 plug standard is rated for 50A, right?. I’m thinking I should be fine with a 10/2 Romex the amp draw from the welder is non-continuous, right? Or should I go with 8/2? Or #8 THHN instead? Breaker should match the wire, yes? So 30A breaker for #10 and 40A breaker for #8?
Thanks for your time.
The first project is adding an exhaust fan to a bathroom and the second is adding lighting and other circuits to the garage.
Background info: San Diego house built in 1961. When we purchased almost 3 years ago we had the main panel upgraded to 200A as well as had a couple of circuits added. If I recall correctly the original setup was like 100A and 2 or 3 circuits for the entire house. GFCI installed on all outlets since the original wiring didn’t have a ground (save for a couple of spots in the kitchen).
The first project, the bathroom, I think I’ve got a pretty good handle on. The current setup is switch to an overhead fixture. Behind the switch it looks like a pair of 2 wire cloth braided cables were run. The switch breaks the connection of the black (hot?) wire and the white (neutral?) is spliced with a wire nut.
My plan is to:
* Go up into the attic and run a length of 14/2 NM-B cable from the switch box to the overhead fixture. Approximately 15 feet.
* Replace the single switch with a duplex switch
* Use a short length of black 14AWG THHN wire to connect the original hot splice joint to the secondary switch
* Connect the primary switch as original
* Connect the white Romex wire to the original neutral splice joint.
* Connect the black Romex wire to downstream end of the secondary switch
* Wire exhaust fan and light as indicated in instructions.
Sound about right? Since I’ve got no ground, I’m assuming I just leave it hanging and leave the safety duties up to the GFCI located upstream.
The garage will be a little more involved. The previous owners had converted the garage into a “livable” area. I’ve since removed the carpeting, and false ceiling, but the walls are finished with drywall and mud. The wall that shares a wall with the house is stucco (I think this was original). In addition they added electrical outlets behind the drywall, but it’s all off the living room circuit.
I plan to leave the original wiring in place but I want to add:
* 1 20A 120V circuit for tools
* 1 240V circuit (single phase, amperage unknown)
* 1 20A circuit for lighting and other uses (drop light, etc.). Lighting will be handled by 2 switches.
Lighting
I’ve been gifted 7 dual bulb 4 ft T12 fixtures. Best I can tell, with all of them running, this will draw about 4.7A. If I didn’t have anything else plugged in, a 15A circuit would probably be fine. However, I plan to install outlets at each lamp so I can replace them when the ballasts **** out. As such, going with 20A means I have another circuit to use in the garage for tools and stuff.
The panel is located at one corner of the garage and I want to put the light switch at the opposite corner (near the door leading into the house). It is my understand that I could simply run the 12/2 Romex along the rafters and joists, along the perimeter of the garage, and then down the wall to the surface mounted electrical box. However, I’d like to protect the exposed vertical cable that will run from the joists to the box (approximately 5 feet).
Based on what I’ve read running Romex inside EMT conduit to a metal box is allowed for short sections according to the NEC. Some city codes don’t allow this. There is concern of overheating due to the extra level of insulation and of course everything needs to be grounded properly. However, for a length this short, I can’t really see this being a problem. And besides, how else protect this short section of cable? It would seem silly and wasteful to run Romex to an overhead box and then run armored cable or THHN inside EMT for just a few feet to another box. What do you think? I understand I also need to install a bushing or insulator on the exposed end of the conduit so as not to cut the wiring.
This box will have 1 duplex receptacle, and either 2 single switches, or 1 duplex switch. Out of this box I will run 2 Romex lines up into the rafters to handle the lighting. So that means I want to run 3 12/2 Romex cables into this box. At each termination point I’ll have one of those blue plastic outlet boxes nailed to a rafter. After I install the outlets I plan to cover up the exposed rafters, insulation, and wiring with some of that reflective foil stuff you see in industrial applications.
What size EMT conduit do you suggest? 3/4”? 1”?
Is there a smarter way of doing this?
I picked a metal box mostly because it looks professional. Grey PVC would work as well, right?
How would I attach the metal box to the stucco? Or is it better to find the studs and attach there?
Tool Power
The garage is small, and I don’t own a lot of power tools. Besides the preexisting shared line, how many additional 120V circuits are really needed? It seems to me I could probably do just fine with 1 20A circuit to power most stuff. I don’t have room for a drill press, table saw, or lathe and I can’t imagine using more than 1 high amperage tool at a time. For the additional 120V circuit, I’ll probably have 1 or 2 outlets along the side wall and 3 or 4 outlets along the back wall. Much like the lighting, I’m thinking metal boxes with short sections of EMT conduit to keep things nice and tidy along the visible portions of the walls.
I also want to add a 240V circuit. Eventually I’d like to buy a small welder and best I can tell they usually draw less than 25A according to the manuals (looking at Miller and Lincoln brands). A large air compressor draws less than 15A and it’s unlikely I’ll be running them at the same time.
For the plugs, it appears that 6-50 is the standard for welders so I’ll probably use that at all the 240V outlets. The 6-50 plug standard is rated for 50A, right?. I’m thinking I should be fine with a 10/2 Romex the amp draw from the welder is non-continuous, right? Or should I go with 8/2? Or #8 THHN instead? Breaker should match the wire, yes? So 30A breaker for #10 and 40A breaker for #8?
Thanks for your time.