Rewiring Old House - Help/advice Please? - Electrical - DIY Chatroom Home Improvement Forum

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Old 09-26-2009, 12:52 PM   #1
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Rewiring Old House - help/advice please?

I see a few of these threads, but none quite answer all of my questions:

I am currently in inspection/negotiation phase of buying a house with 100% Knob and Tube wiring. I am an IT professional who works occasionally from home and could benefit from having grounded outlets in every room. I plan to live in this house for at least 7 years.

The house:
Contract price $56k
Recent appraisal $70k
Total estimated rehab costs: $13k
Tax credit of $5600

Cape Cod 1.75 stories
~1000 sq ft
unfinished basement
accessible attic
2 BR + 1 Bath upstairs
Living, Dining and Kitchen downstairs
Updated 100AMP breaker box
... probably some lead paint.
I have had 2 quotes on it for complete rewire of $8000 and $10000. I also received a revised quote to replace all visible (basement and attic) KnT for ~$2000.

I don't want just a wiring face lift. I would be doing this for three reasons:

1) Functionality - I am a techie and need grounded plugs everywhere
2) Resale (ease and value) - while this isn't quite an added value, rewiring will ensure that it won't be a negative value, thus easier to sell.
3) Home insurance premium reduction - est. 30/month savings over 7 years is ~$2500, so ultimate cost will be ~$5500.

Is it worth it? I can still walk away...

How should I be shopping to reduce costs? How do I talk to a contractor to ensure best outcome?

How can I personally reduce costs? Can I do some of the work?

Can I rewire it myself and hire someone to come out and hook it up...

... and if so, what are Ohio/National codes, processes, headaches, etc. I am a PC techie and I understand gauges and diagrams enough to rewire a new construction, but I have little experience drilling through things and fishing (once for a 5 home run install of cat5 in a 4 room single story). I suspect going on the outside through conduit from basement to attic, then dropping down interior walls would be easiest. Am I required by code to have a minimum number of outlets in this room? I am aware of spacing restrictions, but what if I only put 2 outlets on two interior walls and leave the other two exterior walls without power?

Finally, do I have to actually remove the KnT from interior walls or can I just leave them and just disconnect them from the breaker box? ... because once I cut into the drywall, it is technically "exposed"... so I am guessing get rid of the "exposed" KnT, right?


... and thanks!

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Old 09-26-2009, 01:03 PM   #2
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You should talk to your building inspector to see if you can do all the work yourself.
I tear things down and build them up.
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Old 09-26-2009, 01:12 PM   #3
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Agreed... but I do know so much as I can at least run lines. Mainly, I am wondering if I can just run a couple easy ones to each upstairs room and just patch up old outlets on the hard runs.
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Old 09-26-2009, 01:23 PM   #4
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Definitely check with your local inspectors to see how much you can do, what permits you need etc. Your insurance company may want to see documentation for you to get the credits. Depending on how rigid things are in your area, you may also find your electrician getting squeemish since he or she will ultimately be legally responsible for signing off on things and wiring that you did. Silly perhaps but only because too many homeowners have done Micky Mouse things in the past.
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Old 09-26-2009, 01:32 PM   #5
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Major rewire you are usually required to bring up to current code

Dedicated 20a GFCI to the bathroom
Bedrooms need to be AFCI
Kitchen needs (2) dedicated 20a circuits
Hard wired smoke alarms

Outlet required every 12' & on every wall
I usually do outlets every 8' or even less depending upon the room
I run everything for the 1st floor thru the basement
Conduit up the outside of a house is ugly & says "quick fix"

Don't do the visible replacement
That means they then connect new ire to K&T where it goes up into walls
Waste of time & $$ IMO

I'm running 2 Data, phone & cable lines while I'm rewiring my house to every room
Some rooms will have multiple jacks
I'm allowed to do my own electric here

Yup, check with the local building Dept
Also verify with an electrician that they will hook you up & finish the job your start.
Possible some will not do this or even charge more

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Old 09-26-2009, 03:03 PM   #6
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Rewiring an old house nearly always requires wall repair. It is impossible to run entirely new wire everywhere without making some holes, so I would make sure you figure that into your total costs.

Make sure whomever you hire is reputable. I've seen more than one project where only the receptacles were replaced, and a jumper placed on the device itself between the ground and neutral terminal. It fools a receptacle analyzer into indicating the presence of a ground when in fact there isn't one.

It is usually permissible to abandon the existing wire in the wall, so long as none of the old wires remain in your receptacle, light, and j-boxes. This is a great question to ask your inspector since it's his eye you'll have to please in order to get passed.

I agree that you'll have to bring the entire house to current codes, including smoke detectors, GFCIs, arc-fault, etc. I'm assuming your electrician is also including a service upgrading in his scope of work.

Knob and Tube is certainly insufficient for modern appliances, computers, electronics, etc. If it has remained untouch in the walls and is left alone, it can continue to do the job it was originally installed to do.

Unfortunately, most houses that are old enough to have K&T, have been worked on a number of times over their lifetimes and very often have had unsafe modifications and tie-ins to the original wiring.
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