Electrical Wiring in the Home/Wire size, and switch


QUESTION: I hooked up several spotlights with number 10 wire directly to the fuse box. The breaker is used as the on and off switch. My son now wants the switch in the kitchen so he doesn't have to go down cellar every time to turn them on. I know I can break the wire at any point and run the neutral leg to a single pole switch in the kitchen. Here is my question, can I use a number 14 wire for this or do I have to stick to the number 10. Thanks for your help

URL: http://able2know.org/topic/302162-1

ANSWER: Robert Wilber
Philadelphia Licensed Electrician
Philadelphia License # 3516 - 16765
Electricity is dangerous!
You can be injured or killed!
Improper installations can cause fire, injury and death!
Are you qualified to do this work?
National Electrical Code definition, NFPA 70 2008 Article 100: Qualified Person. "One who has skills and knowledge related to the construction and operation of the electrical equipment and installations and has received safety training to recognize and avoid the hazards involved."
Electricity is fire in a box! Death on a leash!
Always check with the local “Authority Having Jurisdiction” for an official interpretation before making installation decisions.
In Philadelphia, it is unlawful for anyone except an individual licensed by the City of Philadelphia to install electrical equipment and wiring.
Homeowners are not allowed to install wiring.
The owner of any property wherein any such installation is discovered shall be issued a violation by the Department of Licenses and Inspections.
The limited exceptions include replacing devices and fixtures at existing outlets.
Contact the Department of Licenses and Inspections for more information.
You are more likely to be killed by 120 volts than any other voltage [120 volts creates the PERFECT fatal current through the human body's electrical resistance!]
This information is provided for the use of parties as they see fit!
I am not responsible for the application of this information by any party, including those lacking sufficient skill or knowledge to perform these steps safely and any hazard created is the SOLE responsibility of the user.
Define "several"
What is the total wattage of the lamps?
What size breaker protects the conductors to your lights?
Why did you use 10 gauge wire?
Your knowledge is erroneous. It is completely improper and contrary to the National Electrical Code to open the grounded conductor [neutral] and leave the ungrounded conductor [hot] connected and energized. Always switch the hot.
If the circuit is protected by a 15 amp breaker, why would it not be acceptable to use 14 gauge wire, which is rated for 15 amps, for the switch?
You need enough slack to install a box where you want to install the splice for the switch leg.

---------- FOLLOW-UP ----------

QUESTION: Hi, I used a number 10 wire as the lights equaled 3000 watts, using ohms law 3000 divided by the current (120) equals 25 amps which requires a number 10 wire and a 30 amp breaker. I already installed a box where the split could be made at some point, please advise,  Thanks

I have a lot of bad news for you.
If these lights are going to be on "continuously" [3 hours or more] then the maximum allowable loading is 80% of the rated ampacity of the conductors. That would be 24 amps for 10 gauge. I know it is only a little bit high, but wrong is wrong.
Then, since your load is that high, your switch leg would have to be 10 gauge.
Then, you would have to have a switch rated for 30 amps.
Now, the bad news.
It is only allowed to use a thirty amp lighting circuit in non-dwelling applications.
This needs to be broken up into two 1500 watt 20-amp circuits.
My suggestion would be to run them through a relay and control the relay from the kitchen. You could even use a latching relay with a 24 volt coil and install a low-voltage switch to control the relay.

Sorry for the bad news. Good Luck.

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Robert Wilber


Licensed Philadelphia electrician serving Delaware, Chester, Montgomery and Philadelphia County in Pennsylvania. I install and repair residential, commercial and industrial wiring and lighting. Troubleshooting and repair of problems that stump other people is my favorite. I am willing to help people figure out why things don`t work. I understand motor controls, transformers and machine wiring. I do not teach basics to novices or do free design work.


Experience in the area I have 44 years experience in residential, commercial and industrial electrical construction and repair, 480 volts and below. This is not to be confused with one week repeated two thousand times.

44 years experience in residential, commercial and industrial electrical construction and repair

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