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bgrieves1 08-14-2012 12:49 AM

How to run circuits from outside main panel?

I have a very old house with Knob and Tube wiring.

I just want to rewire the whole thing.

I would like to just use PVC conduit on the inside walls of the house to keep from complicated remodeling of walls, etc...and to protect from asbestos.

How do I run several new circuits through the exterior wall? My main panel is located outside my house....

do I install a LB joint for each 220v circuit....say maybe for stove and one for dryer...and put these LB joints through the wall and then run PVC conduit inside the house to my two 220v outlets...?

..and then install a subpanel on the inside of the house for all the 30 amp and below lower voltage lights, etc? recap: Install two 220v circuits coming from outside main panel with each circuit going through an LB joint through the external and through PVC conduit on the inside of the house to the 220v outlets.

Then put in a subpanel on the inside of the house for all the other new circuits...

sound OK?

I want to totally rewire this old small house. Don't trust this old knob and tube...the outlets are not holding plugs well and they are sparking bad.

Thanks for any help


AllanJ 08-14-2012 06:07 AM

Alternative: Run one short fat (say 3 inch) conduit through the wall at or near the outside panel with a junction box on the inside and a junction box on the outside. Run individual new wires from the outside panel through this fat conduit non-stop to the various lights, receptacles, dryer receptacle, etc.

For running conduit or Wiremold, the junction box on the inside needs to be large enough that there are enough openings (knockouts) for each small conduit. Outside you may be able to use two or three medium sized nipples between the junction box and the panel on the outside if one fat nipple won't fit.

Do not use a receptacle where the plug does not fit tight or where you get any sparking. This is a loose connection that will get very hot. Such a loose connection between plug and receptacle is often the cause of a fire that is blamed on knob and tube wiring.

You can safely replace the receptacle, keeping the K&T wiring in place provided that the insulation does not crumble as you are making the replacement. Use a 2 prong, not a 3 prong, receptacle.

bgrieves1 08-14-2012 08:17 AM

Thanks Allan..can also ground k & t outlet w/ green pigtail
Thank you so much Allan....I have been so puzzled about how to get multiple wires through the exterior wall from the main panel outside.....

so use a junction box...LB....junction box.....I guess I can run whatever I need
if I use a big enough JB, LB.

Black and Decker complete guide to wiring showed me on their DVD last night how to ground a two prong K and T outlet with a green pigtail screwed into the metal box.....

Yes, I think that is wise just go ahead and upgrade some outlets.
That shouldn't take much time or money and it is something simple enough for me to do immediately.

This would be a quick, easy, cheap way to immediately make this old house safer and less of a fire hazard.

Thank you so much for your help.....


parman 08-14-2012 09:00 AM

Large LB from panel (2"?) to inside house.

From piece sticking into house, mount a junction box (12"x12"x4"?) with the piece coming into the back of the junction box.

From junction box, you can run what ever you want.

Make sure, after you are done pulling your wire and stuff, to weather seal around the LB as it enters the house. Also, just as important, to weather seal the INSIDE of the LB. We use a product called "Duct Seal" for sealing the inside of conduits. It's found in the electrical section of Home Depot, etc. and it is a putty like consistency.

I would not ground your receptacles to the back of a metal box unless that metal box is grounded to your electrical system some way. If you have entirely Knob and Tube, then your box is not grounded and grounding your receptacle to it will not do anything except heat up the metal in the event of a fault.

If you want 3-prong receptacles, you can install GFI receptacles as a replacement for your old 2-prong receptacles. You can feed downstream regular 3-prong receptacles from the load side of a GFI receptacle to help save money on cost of adding a whole bunch of GFI receptacles.

bgrieves1 08-14-2012 09:18 AM

ground k and t outlets w green pigtail to back of box?
Thanks Parman....

The main panel looks like it has been I think they upgraded that and tied onto the k and maybe that is grounded.

Don't you think if it sparks that green pigtail to the metal box might help head off a fire just a little bit?

I guess it would be worth the effort and fairly small amount of money if it is grounded up by the breaker box....very small house.

Just seeing some pretty big sparks coming out of these 73 year old K and T outlets.

Have a good day,


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