Hot Topics: Tips for Running Wire Through Existing Walls

A group of wires sticking out of a hole in a wall in a construction project.

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This DIYer is new to the world of electrical home improvement work, and wants some tips and tricks for how to get wires through existing walls. The forum weighs in on the topic, with advice ranging from using clothes hangers to inspecting construction sites.

Original Post: Tips for running wire through existing walls

AlarmBoy123 Member

I want some tips for routing wiring through walls for new hardwired contacts or even a new install. Will it be easy? Hard? I'm a newbie so any help would be helpful!

MrRonFL Forum Topic Moderator

A lot depends on the structure of the building. Modern houses are typically more difficult, as there tends to be more bracing and insulation in even interior walls. If you can easily get at the floor plate from below, or the top plate from above, you are halfway there. Otherwise, fishing wire is as much art as science.

marksr Forum Topic Moderator

When I installed my system I took a clothes hanger, straightened it out, taped my security wire to it and pushed it through a hole drilled big enough to accommodate both.

PJmax Group Moderator

When I first went to work for an electrician, I traveled around to different new construction sites. The only way to be able to fish wires through walls and throughout the house is to see one being built. Try to find a house being built in your area. Bring a bribe like coffee and donuts and you'll get a personal tour. Bring lunch and they may come to work for you. You must learn wall construction. You need to see why the wiring can't just go up through the wall. You need to see how the walls interact with the floor and the ceiling.

I learned many years ago from different electricians. Now, I install high end alarm systems, too. We don't hardwire doors and windows any more in an existing home as the labor to run the wire is now offset by using wireless devices. We do hardwire the keypads.

Chandler Forum Topic Moderator

So when I replace doors and encounter the hardwired sensors, it is likely they are being replaced by wireless? I always tuck the wires, capped or taped, neatly back into the hole in case they are needed later. Come to think of it, the client did have wireless magnetic breaks above the door. Live and learn.

PJmax Group Moderator

Not at all. If the house was hardwired, then those switches should still be used. I'm talking about a built house with no prewiring. Then, wireless is a viable option.

When you look at a wall, there are studs running parallel that are nailed to a top and bottom plate. You can drill from the attic down to the second floor. You can drill from the basement up into the first floor wall.

Some problems: finding blocking in the wall that needs to be drilled, a low roof creating making it almost impossible to drill down, all outside walls are insulated ans double the effort to run wires.

AlarmBoy123 Member

What do you do if you run into a stud, though? How do you drill through a stud when you have the hanger / fishing device?

MrRonFL Forum Topic Moderator

They make long flexible bits for this sort of retrofit work. They take a little practice to use well, but are very effective. You have to be careful to scout out any likely electrical, or other obstacles that might be in the way.

As previously stated, wire fishing isn't as much difficult as it is tedious, and requires a little understanding of building structure, and a lot of forethought.

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