Room has wired 3-way switches, but light fixt is missing. Fixt box has 2 sets of wires (2-wires + gnd) coming in. How do I connect a simple light fixt?

Mark

• 704 Answers
• Posted on Sep 10, 2009

SOURCE: wiring dimmer to knob and tube

You should attach the green grounding wire to the metal box using a green grounding screw. You don't want to leave the wire loose, as any contact with the switch screws could cause a short.

Also, you should wrap the switch with at least 2-3 complete wraps of electrical tape to prevent the screws from contacting the sides of the wall box.

As a side note, you should likely have a complete check done on your house if you still have knob and tube wiring installed, as the dangers associated with this very old wiring are many. Typically, older K&T wiring was used in homes well over 60 years ago and houses then only had minimal electric current drawing devices, such as lights and a couple of other small appliance devices (toasters, coffee pot, TV and radio, etc.)

The problem with older homes with K&T wiring still in use, is that the circuits can be easily overloaded with modern electric convinences and lead to a possible fire situation, especially since there is no dedicated ground to help mitigate short circuits, etc. Also, the rubber based insulation used on this type of wiring deteriorates after 40 years (+/-) and rodents tend to chew on exposed wires in attics and crawl spaces.

I don't wish to alarm anyone, but as a Licensed Master Electrician, I've seen and done my share of repair work involving Knob & Tube wiring and even had a couple of homes that had a mix of it and other, newer wiring, that I've completely rewired. Many states require K&N wiring be replaced before a home can be sold, so getting a jump on it will make your home safer and better suited to operate all the devices that people tend to have, in today's society.

Hope you find this Very Helpful and best regards!

SOURCE: 4 can lights wired to two 3 wire Lutron

The interior flood light bulbs were the new flourescent energy savers. I replaced them with incandescent and it worked with the dimmers.

SOURCE: I am replacing an old dimmer switch with a new

ON one side of your switch it is connected with a small peice of metal or should be. That is why it only explains 3 wire instead of 4. If you look you can find the one you need with 4 spots to put your wires. Just look or ask your store for what you need. They can be very helpful in helping you find what your looking for. Hope this helps.

SOURCE: I would like to install

The circuit you are working on is a 3-location circuit - where two of the devices were 3-way switches, and the remaining device (the one you are trying to replace with a dimmer) is a 4-way switch. Standard dimmers like the one you're using CAN NOT be used to replace a 4-way location. If you wanted to use it to replace either of the 3-way switches, that's no problem - but what you're doing right now will not work.

If you absolutely want to dim the lights from that specific electrical box, my suggestion is to upgrade to a "smart dimmer" where instead of a basic dimmer and two light switches, you have three devices that talk to one another and all dim the lights together.

In terms of your ground wire questions - ground wires certainly aren't necessary to make the whole thing work - rather they're there for safety. Sometimes installers will ground the device by connecting the ground wire to the backbox (assuming its metal) and then rely on the mounting screws on the dimmer or switch to perform the grounding. There are some code rules/exceptions for allowing the device to not be grounded (usually when its in a plastic, non-combustible backbox). If you want to make sure everything is completely up to code (which are usually goverened by local municipalities), you should consult a licensed electrician - but above all else, just use good judgement. Long story short, if the devices weren't grounded before, you can't make it any worse.

SOURCE: I'M REPLACING AN OLD LEVITON

with a three way switch like this, you will have two traveller wires and a common wire. Look in the instructions for the switch or on the back of the device itself to see if there is a wire labeled "common" or "com". This common wire from the old switch hooks up to the common wire on the new switch. I did a bit of searching on the leviton 6602, but couldn't find anything specifically about the three way version (I would venture to guess, however, that the red wire on the old switch is the common). The common on one of the three way switches will always be a constant hot (or power) wire...the common on the other three way switch will be the "switch leg" or the wire that connects directly to the light. The two travellers go to the other two wires. Check the pamplet that came with the lutron device, it should show which wire is common and which are travellers.