Electrical Wiring in the Home/ceiling lights


I have a room 17 x 29 with 3 3 light ceiling lights, I am removing the ceiling for some other work and how many of the can ceiling lights would I need to replace the old ones that hang down and still provide enough lighting for a room that size.

Robert Wilber
Licensed Philadelphia 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 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.
That being said, I believe my profile states that I don't do free design work. Insurance provider limitations mandate that I only design contracted installations.

That aside, I can provide some guidance.
You have to take a number of factors into account:
the ceiling will be unlit, which will make the room darker, since there will be no reflected light from the ceiling.
ceiling height?
purpose of room?
wall color?
distance of various surfaces from ceiling?
  tables?   chairs?
furniture layout?
desired light level on various surfaces?
  do you want to light floor? walls?
light output of each fixture?
lamp visibility?
  hidden lamp?  exposed?   
do you want to be able to read in the room?
other point lighting sources?
circuit loading?   can the existing circuit carry the new lighting or are additional circuits needed?

You need to create a floor-plan drawing with furniture placement

I think that you will find most lighting outlets will have a design group that can answer your questions, either for a fee or in consideration of your fixture purchase.

Informational meetings, drawing preparation and design can cost from $500.00 to $1,000.00.

Best wishes for success with your project.

About Electrical Wiring in the Home
This site answers questions related to home electrical wiring, home wiring, general electrical help,and other electrical questions related to aleternating current (AC). You can find help on the National Electical Code, home electrical issues, wiring electrical outlets, installing lighting, electrical grounding, and general electrical help for do-it-yourself projects not require an electrician. If you do not see your home electrical wiring question answered in this area then please ask your electrical wiring question here

Electrical Wiring in the Home

All Answers

Answers by Expert:

Ask Experts


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

©2016 About.com. All rights reserved.