You are here:

Electrical Wiring in the Home/replace light switch w/Timer in drop-down box


Hi: I have a porch light switch in a drop-down box with only a single black and a single white wire coming into the switchbox. Is there any type of 7-day programmable timer that will work with this type of wiring?

It seems most of these devices require a neutral conductor to function.

Andrew sure, from basic low cost to fancy electronic,        

In the switch box is basically the hot lead to the light,  they should have put a little set of black marks on the white to show they took the white and made the other half of the switch leg.

Now someone behind them will know which is THE hot black and the white is the jumper   a single pole switch is,  then one of the wires to the load,   and done correctly the hot, it is simply a convention of how they set things up over the years.

So just like your switch now, you could use a mechanical timer,  if you want fancy,  you need 115 volts to the timer  and will need to feed another lead from the light

Go here,  most are wired as I described but some are middle runs and might switch two leads already,  they try and keep the full circuit away from people.

Can you determine if your switch is switching both sides of line or just one?

One way to tell and the green ground doesn't count,  from white to black will read 115 or whatever your voltage is,  117   120   not every voltage is exact on the penny.

A 6 dollar ohm meter will tell you that  the voltage will aways be there if they brought 115 into the switch box.

If the white and black are on the same side of the switch  it is likely you are just cutting a wire into and back with a switch      if you have plenty of wire and can cut the leads off close to the switch and take it to any hardware store,  there you can see all your choices, and trims,  and options and costs.

Whatever make sure the breaker that circuit is locked off,        !!!!

They have come up with easy  to install one line side, timers with options because lots of switches have just one side of line    forget colors of wires, it is what they are that matters,

Above is a 7 day timer but it needs the power at the switch,  It seems like yours is, but I just cannot say without seeing or measuring,   but yes it is possible and running a jumper if needed is normally no big deal,  if your wires are on either side of the switch not on the same that would short them out if they were load power,      see the deal?

I would invest in a volt meter,  they have them so cheap now, and there is always a use for measuring something,     then you KNOW  but yea there a lot of timers that don't need line neutral and load,  just the 115 power starting in the switch box.

Take a look at the links then a trip to the hardware store,  and get your pricing and looks and all that scoped out,  
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


Will Babbitt


Electrical issues of all types, wiring, control, appliances, components, specialty in Electric MOTOR or APPARATUS trouble shooting, electric motors, electrical problems, single phase, three phase, DC, capacitors, elevator MG-Sets, modifications, reverse engineering, VFD Drives, single to three phase convertors. Repair of most any electrical/mechanical/electronic apparatus, OEM, AC, DC, Industrial Applications, Three phase, single phase failure mode, determining the root cause of the equipment failure BEFORE failure repeats, Antique appliances, electric motors, fans, ceiling fans, base mount fans, poor equipment performance, Modifications, habitual failures, vibration, redesign, obsolete issues, collectible items restored, rewinding. Owner of EMR Repair Inc More information on electric motors, under Engineering/Motors Ask about any electrical or mechanical problems in the home, office, or even at your work. B2B or business to business CONSULTING I can do but it would be a much more complex issue, that would require a significant amount of time. from there we can discuss and begin work on about anything. Industrial electric motors, controls, troubleshooting, vibration, alignment, any type of industrial or commercial electric/electrcical equipment For the home owner, renter, apartment if you have odd things going on, describe to me, photos are normally very helpful, appliances, heating and air conditioning issues, light switches, installation, DIY PROJECTS FOR THOSE NOT EDUCATED IN ELECTRICAL, we can do some things, but for safety and sanity reasons, I may refer you to a local electrician, and help you find one, help you with pricing and even speak directly with anyone you hire if you have issues,


Over thirty years with a major repair and sales company, VP of Operations, and former owner of my own specialty repair shops, MEAR Services local to Kansas City Missouri EMR Repair Inc., located in Kansas City Missouri, 2014 sold both businesses to JCI Industries, Lee's Summit Missouri Evaluation and repair of electrical/mechanical apparatus. Electrical and mechanical repairs, trouble shooting including, vibration and balance issues. provides this service, and the huge costs to provide help on about any subject. They provide the servers, the people to vet the experts, costs that would be the same as operating a good sized business, They should be appreciated for what they do, the huge costs and the great help they provide for free, Electric motor questions, can be answered here but there is a dedicated category that has other experts to help and add to a solution. Other common questions, are noises in the walls, breakers tripping, devices not starting or shutting down for no apparent reason, smoke alarms buzzing, thermostat change outs, or sizing wire or needing information for a new project, but anything can be resolved, anything, with enough effort and patience, DIY, with electrical is possible, but in most cases the use of a simple ohm meter or volt meter is needed, they can be purchased at any hardware store for a few bucks. If you have smoke, or smell smoke, don't be writing me, call 911 the Fire Department has no problem looking for smoke smells, better then spraying water on a blazing fire. DO NOT GET CAUGHT INVESTIGATING AND TRAPPED IN A BASEMENT LOOKING FOR A BLOWER FAILING< As to the tip jar, it is up to you, it is appreciated, every expert spends out of pocket that I know, we spend on IP time, computer wear, printing documents, books, and of course our time, but if we prevent a $400 service call, we did well,

Former IBEW, EASA, IEEE, UL, ..............


10 plus years, various Technical Schools, followed by Industrial College Credit and non Credit Courses, electronics courses, experience in most any electrical apparatus, electric motors and generators, AC OR DC, fractional to above 5000HP, other electrical apparatus, slip rings, sleeve [plain] bearings, lubrication, identification-no data plate, control components, service and sales. I have continued night schools for decades, the list is extensive. I have been in the business of repairing most anything with wires or mechanical parts for decades, I have some helpful hints and directions you won't have to dig up. Or hopefully not have to pay a huge service call invoice to find.

Awards and Honors

Past/Present Clients
Federal Government, National Weather Service, NOAA, Commercial Power Plants, Major Vehicle Manufacturers, Printers, Other industrial and Commercial Businesses

©2016 All rights reserved.