3 posts / 0 new
Last post
rewiring an old house

Our house was built circa 1911 with half+ of it still with original wiring.  I believe it is called knob and tube with cloth wrapped wires.  I am concerned for safety, age and with modern appliances, circuits get overloaded.  We also have an older circuit box with breakers that look like large light switches.  I know I need to get an electrical contractor for this job but would like pointers as to questions to ask them, issues I should know about, etc.  The interior of the house is not sheetrock; it is either thin plywood or some kind of plaster.  Is there a way to do this job without totally gutting the walls?  Any ideas, pointers, direction you could supply would be greatly appreiated.  Love your magazine!

Re: rewiring an old house


There are so many variables, it is diffcult to give an exact answer. Mostly likely what you have are plaster walls. They are created with lathe strips behind the plaster. The lathe is what holds the plaster on a vertical surface. Yes, you can re-wire the entire house without damaging any of the plaster around the holes that will be cut. I have re-wired many older houses, there is always a way without damaging the walls, ceilings or floors. You will have to follow the rules set in the NEC code. Then there may be some rules set by your local government. The office where you purchase a permit can tell you everything. Make sure that you find an electrician that has worked on older houses. They are not the same as people who have not.

Some of the more important things would be what size electrical service do you plan on putting in the house? Actually, you do not have to have an electrical contractor if you do all the work yourself. If you have never worked as an electrician, I would suggest that you hire a qualified company. Do not be in any hurry to chose the company that submits the lowest bid. You will want to specify everything they do and the quality of materials they use. I would never purchase any electrical equipment from a box store. Visit one of your local electrical supply houses, and develop a relationship with them. I would never wire a branch circuit using #14 wire. Even though that is allowed, the NEC Code is only a starting point. I would never use aluminum wire, any where in the process, and that includes the service from the pole to the structure. I would put the service entrance underground. I like using MC cable and not romex. It takes a little more time to pull, but nothing likes to eat it. After all, it is metallic. I like Square D equipment, they have been aruond for many decades. But do not use the Homeline version, use the QO version. You need to determine the size of the service that you want, or need. Today, most houses far exceed the 100 amp service, and even some the 200 amp service. I wired out Victorian house with 600 Amp service. One 200 amp panel for each floor, amp sub panel for the kitchen. The code requires that all new circuits for most living spaces be AFCI/GFCI circuits. I used AFCI/GFCI breakers and not the outlets. I wanted to have the highest quality protection that I could use. I used AFCI/GFCI breakers for every circuit I could, excluding some of the 2-pole circuits. I suggest using #12 or #10 wire for every small branch circuit. I went at least one size larger on all the wiring in the house. Where a 30-amp dryer circuit can have #10 wire, I used #6. Less resistance, less heat, and less currect being pulled. Our electric bill has dropped greatly after the cut-over.

You will want a contractor that will take their time, and not try to do this work in a week. I also pulled all the wiring from the panels thru one joist bay. Some will not take the time to do this task in a neat manner. This way, all the wires are tucked up out of the way of anything else that I may want to add later, or have currently, such as HVAC ducts, basement lights, etc...The three panels are fed from the meter base thru 4" Conduit, no wires just fasted to the joists. They are well protected from damage. Even though 3" would have been large enough, the heat will disapate better by using 4". I never used any PVC or plastic pipe, I do not like PVC pipe for Electrical.

I know I went above and beyond the normal, but I never have to worry about it ever again. No chance of anything being damaged, and I have more than enough space in any panel to add another circuit or two when needed. I have not idea what the future will be, but it seem that more and more electrical devices are on the way. Just like 40 years ago, a 100 Amp panel was fine for most homes, but not today. When a circuit is overloaded, the wires too small for the amount of current being used, they get nice and hot, and that causes fires. I never used a junction box any where in the design of my electrical circuits. Only conenctions that were made, were made in the outlet or switch boxes in the living areas. I used twist wire nuts and taped each one, plus I taped the devices where wires were connected. I used metal boxes, I do not like the cheap plastic boxes. Never use any of the old wiring, or tie into any existing circuit, replace it all.

I would suggesting finding a contrator that will add the new service parallel to the existing. Once the service inspection is complete, then setup a date with the Electrical Provider in your area to perform a cut over. They will switch the power to the new service. You will be then able to use the new service and still continue to add more circtuits. The completed inspection can come after that.

Like I stated, there are so many variables, the answer is "It Depends". But if you do it right the first time, you never have to touch it again. Plan your electrical service for 50 years in the future. Make sure that you use the highest quality equipment that you can find. SquareD is my favorite. 50 years from now, if you need to add a new circuit, you will be able to find a breaker that will fit the panel. I have done a few houses that was not the case, and we ended up having to replace the entire panel just to be able to add one circuit.

If you have specific questions, please post them.


Handy Andy In Mt Airy NC

Re: rewiring an old house

Wow! That's a lot of good information. Thanks Handy Andy.  J

Sponsored Stories

TV Listings

Find TV listings for This Old House and Ask This Old House in your area.