Shop lighting wire diagram help

Reply

  #1  
Old 10-08-16, 10:10 AM
Member
Thread Starter
Join Date: Feb 2014
Location: usa
Posts: 11
Shop lighting wire diagram help

I am wiring my shop and my electrical skills are not very strong. I want to figure out my wiring plan for the lighting and I was hoping someone could make sense of my wiring plan sketch. I don't know the proper symbology, but I tried to label everything so it makes some sense. I am attaching 2 sketches. One of the diagram and one of the elevation view of the wall where this is going.

First, I plan to run all the shop lighting off of 1 20 amp GFCI/AFCI combo breaker. The total wattage for all lighting is less than 900 watts (all LED).

I will ultimately have 7 sets of lights, each set controlled by 1 switch (no 3 way).
5 of the 7 sets are detailed in the diagram. The other 2 (F/G) are further away, but will be wired up the same same...

Do my drawings make sense, and will this work?

Name:  IMG_0295.jpg
Views: 4403
Size:  28.6 KB
Name:  IMG_0298.jpg
Views: 1105
Size:  18.2 KB

Thanks!
Scott
 
Sponsored Links
  #2  
Old 10-08-16, 11:20 AM
Member
Join Date: May 2015
Location: USA
Posts: 3,138
You need to bring a neutral (white wire) into every switch box, even if it's not used at this time. Many devices such as motion sensors and timers now require a neutral connection so code now requires a neutral in every switch box.

If total is really only 900 watts I suggest you use a 15 amp circuit and 14 gauge wire, it will be *way* easier to deal with so many wires if they are 14 gauge rather than 12.

Are you going to get a giant 5 or 7 gang box for all the switches? If not, you can separate into multiple boxes, but will need neutral in each.

With so many wires in your junction box, you have to really watch the total box fill. DAGS on box fill calculation to see what size jbox will be required. I doubt a 4x4 will be anywhere near big enough. Make your life easier by oversizing the junction box.

Will everything be in conduit? Sure would be faster/easier to use romex at least for the runs to the lights.
 
  #3  
Old 10-08-16, 01:37 PM
Handyone's Avatar
Member
Join Date: Aug 2000
Location: U.S.
Posts: 5,451
I would suggest you run your source power into the switch box or boxes, not the ceiling.
This makes the wiring simpler and keeps a neutral at every switch box. Use #14 on a 15amp breaker as stated already, you will thank yourself.
 
  #4  
Old 10-08-16, 01:41 PM
Member
Thread Starter
Join Date: Feb 2014
Location: usa
Posts: 11
Does each neutral wire going to each switch need to be an independent wire from the power panel, or can I splice off one wire to each switch? Do I just terminate the neutral wire in the box, or actually hook them up to the switches? Does it matter which terminal (upper/lower) I use for this if I hook it up? I will be using 3 double gang boxes for the switches.

what size junction box would work for this? I've got a ton of 12 gauge wire and some 10, and enough 8 for my welder's circuit. Buying a bunch of 14 gauge at this point is not ideal for the budget, but it makes sense for ease of installation...

thanks for the quick reply,
scott
 
  #5  
Old 10-08-16, 02:22 PM
Handyone's Avatar
Member
Join Date: Aug 2000
Location: U.S.
Posts: 5,451
I think you haven't learned the basics, but you drew the diagram, so that's good.

Wiring a light with power at the switch is the easiest way. At each box you have a source cable (brought in from the previous box), a cable going to the next switch box to provide source, and a cable going up to the lights.

Wiring is straightforward:
- 1st box - source neutral is connected to light neutral and neutral going to next switch box
- source hot is connected to hot going to next switch box, with a pigtail to either upper or lower switch terminal
- Light hot is connected to the other switch terminal

Since you are using a 2-gang box, you should have plenty of room for 3 cables plus pigtails, but I can't say that officially.

Edit: Error, there are 4 cables, 2 cables going up to 2 banks of lights. I still think you will be fine.
 
  #6  
Old 10-08-16, 05:03 PM
Member
Thread Starter
Join Date: Feb 2014
Location: usa
Posts: 11
Ok, I think I'm picking up what you're laying down. I'll try to gin up another sketch tonight if I can, to see if I am getting the concept right. You are right, I am weak on the basics. I can follow a blueprint or diagram, but the how and why are still magic to me... I just don't want to do something that will let the smoke leak out of the wires...
Thanks again for the patient responses.
Scott
 
  #7  
Old 10-08-16, 05:22 PM
Handyone's Avatar
Member
Join Date: Aug 2000
Location: U.S.
Posts: 5,451
It helps to remember that the neutral cannot be broken. When stuffing a box, I usually connect the grounds, then neutrals, hot wires last.
As long as you have a source cable, a cable feeding the next switch box, and two cables feeding the light banks, you are good.
This is similar to wiring receptacles, a hot wire and neutral, only the hot wire is interrupted before being sent up to the lights.
 
  #8  
Old 10-08-16, 06:58 PM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 33,597
Likes Received: 13
I'll try to gin up another sketch tonight
Suggestion, to make it less cluttered and easier to draw do not include the grounds. They are not needed for a basic diagram. They are understood to be connected per code.

Here is a diagram of the first three switches and lights the others would be the same.

Name:  G.jpg
Views: 1639
Size:  20.9 KB
Larger Version: http://myphotos.mypclinuxos.com/imag...gerversion.jpg
 

Last edited by ray2047; 10-08-16 at 08:08 PM.
  #9  
Old 10-08-16, 09:39 PM
Member
Thread Starter
Join Date: Feb 2014
Location: usa
Posts: 11
This is great. Thank you very much. One more question. The three 4x4 double gang boxes that I am using for the 5 switches are stacked adjacent to the door. There is no room to attach conduit to the sides of these boxes. All of the wiring will have to come in/out via 3 knockouts on the upper/lower sides of the boxes. I connected the three boxes together with spacers. The knockouts are 3/4"x2 & 1/2" x 1.

Here's a pic.

Name:  image.jpg
Views: 703
Size:  27.0 KB



I would have to run all of the wires into and out of the switches through those 3 conduits. I plan to use an 8x8 (just bought it tonight) junction box above the door to route the individual light segments into their own conduit.
Any problems with this part of my plan? (I did buy 14 gauge wire for the lights tonight too)
Thanks again,
Scott
 

Last edited by ray2047; 10-08-16 at 10:43 PM. Reason: Rotate image.
  #10  
Old 10-08-16, 10:56 PM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 33,597
Likes Received: 13
I would use a box connector between the boxes.

Name:  BB-1!2.jpg
Views: 635
Size:  12.2 KB

I showed cable in my drawing but with close linked boxes I would use individual wires between the boxes. If you use metal boxes, metal bushings and EMT to a metal 8x8 boxes no ground wire is needed* between the boxes (the metal components are your ground). However if power is fed to the first box by NM then the NM bare ground needs to be connected to that metal box.

#14 is fine if the breaker is 15 amps.

*While no ground wire is needed in an uninterrupted metal run some would use a ground wire as extra safety.
 

Last edited by ray2047; 10-08-16 at 11:24 PM.
  #11  
Old 10-09-16, 07:52 AM
Member
Thread Starter
Join Date: Feb 2014
Location: usa
Posts: 11
Perfect, those are the exact spacers I used. Ok, I'm ready to dive in and start bending conduit today. Thanks all!
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes