Electrical Wiring for Light Switches
The Difference Between Commercial and Home Electrical Wiring: In this example a commercial medical building has a 277/480volt system.
Light Switch Wiring in a Commercial Building
Electrical Question: How do I wire two separate lights and switches in one supply junction box?
- I have a junction box with a top conduit that goes to one switch and one light.
- The left side top conduit is the power supply coming from another junction box.
- The bottom left side of the junction box has a conduit for a light and one switch.
- On the right side are two conduits that are controlled by switch #2 which is wired through the bottom conduit.
These are Two Separate Rooms with Two Separate Switches
- I need to know how to wire the orange wire which is confusing to me because that wire is coming from light fixture #1.
- I think the wire should be black.
- There are two wires with black tape and I need to know what they are used for.
This is a Commercial Medical Plaza in Laguna.
I really appreciate your help with this, and why it is wired this way.
This electrical question came from: Chris, a Handyman from Laguna, California.
Thanks for your electrical question Chris.
The Difference Between Commercial and Home Electrical Wiring
IMPORTANT: Here in the USA, commercial electrical wiring is not the same as home electrical wiring.
- For Example:
- The voltage for most commercial light fixtures is typically 277 volts, which is not the same as the home electrical voltage for lighting which is 120 volts.
- Since the voltage is different, the standard used to identify the wires is different as well.
A Warning about Commercial Electrical Systems
- In the example of this electrical question, a handyman working in a commercial medical building which has a 277/480volt system poses a higher risk and danger of electric shock and arc flash hazard because of the higher voltage.
- Due to the extent of this project, and for your own safety, I do not recommend that a handy-person perform electrical work in a commercial environment unless you are fully experienced and knowledgeable.
- Working with electricity, especially higher voltage requires a Qualified Licensed or Certified Electrician.
See More about Electrical Wiring
Checklist for Hiring a Electrician
Checklist for Hiring a Electrician – 10 Tips to Make Sure Your Contractor Measures Up.
Electrician Training Programs and Certification Requirements for individuals who wish to pursue a career as an electrician.
Switch wiring diagrams
Electrical Wiring Diagrams
- Home electrical wiring diagrams are an important tool for completing your electrical projects.
- An electrical wiring diagram can be as simple as a diagram showing how to install a new switch in your hallway, or as complex as the complete electrical blueprint for your new home or home improvement project.
Light Switch Wiring
Wiring a Light Switch – Diagram 1
Fully explained pictures and wiring diagrams about wiring light switches describing the most common switches starting with photo diagram 1.
The following may also be helpful for you:
Be Careful and Be Safe - Never Work on Energized Circuits!
Consult your Local Building Department about Permits and Inspections for all Electric Wiring Projects.
The Safest Way to Test Electrical Devices and Identify Electric Wires!The Non-Contact Electrical Tester
This is a testing tool that I have had in my personal electrical tool pouch for years, and is the first test tool I grab to help identify electrical wiring. It is a Non-contact tester that I use to easily Detect Voltage in Cables, Cords, Circuit Breakers, Lighting Fixtures, Switches, Outlets and Wires. Simply insert the end of the tester into an outlet, lamp socket, or hold the end of the tester against the wire you wish to test. Very handy and easy to use.
The Quickest Way to Check for Faulty Electrical Wiring!The Plug-In Outlet Tester
This is the first tool I grab to troubleshoot a problem with outlet circuit wiring. This popular tester is also used by most inspectors to test for power and check the polarity of circuit wiring.
It detects probable improper wiring conditions in standard 110-125 VAC outlets Provides 6 probable wiring conditions that are quick and easy to read for ultimate efficiency Lights indicate if wiring is correct and indicator light chart is included Tests standard 3-wire outlets UL Listed Light indicates if wiring is incorrect Very handy and easy to use.
Strip Off Wire Insulation without Nicking and Damaging the Electric Wire!The Wire Stripper and Wire Cutter
My absolute favorite wire stripping tool that I have had in my personal electrical tool pouch for years, and this is the tool I use to safely strip electrical wires.
This handy tool has multiple uses:
The wire gauges are shown on the side of the tool so you know which slot to use for stripping insulation.
The end of the tool can be used to grip and bend wire which is handy for attaching wire onto the screw terminals of switches and outlets..
The wire stripper will work on both solid and stranded wire. This tool is Very Handy and Easy to Use.
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Hi, My question is rather simple yet after reading 20 different blogs have come to think it may need more thought. I am remolding my kitchen and it’s in a home built 50 some odd years ago. After removing the walls, insulation and ceiling the wiring used is BX (AC,MC?) depending on your definition. There is no way to remove the wire because they feed different parts of the house. I don’t know what the old electricians were thinking when they ran wire, what a mess. Anyway I want to replace all that I can but how do I connect the old feeds to a source? I don’t have space for juction boxes in these locations. I was told that the ceiling cables can be boxed inside the recess light can with a new power feed? Also can I leave the old cable in say a outlet box and switch boxes along side a new feed and outlet? I hope you understand what I’m trying to say here. Many thanks, Steve
Hi Steve – yes, I know exactly what your describing because I have rewired several homes.
Steve, The existing wiring will need to be identified so you understand the purpose of each cable. Once you have done this then the cables may be either dead ended or terminated, or spliced with a new power or circuit source in an existing wall switch or outlet box, or ceiling fixture box if the space of these boxes permits. I personally would not use a recessed light fixture box for a splice or junction box. Basically, if an old wire or cable cannot be removed then it should remain in an electrical box and capped off. If you install a new outlet or other box then yes, the older wiring can remain in its existing box where you may place a blank cover over it. You may also consider replacing the existing box with a deeper box which could contain both the old wiring and new wiring.
http://www.ask-the-electrician.com is really a walk-through for all of the info you wanted about this and didn’t know who to ask. Glimpse here, and you’ll definitely discover it.