Renovating old house electrical room by room?

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TacoFan

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Hi all,

I have a 1955 house with 2 wire electrical. The house has 100 amp service, a 100 amp main breaker outside, and two panels inside. None of the wiring is grounded. I recently had the main breaker replaced due to a faulty breaker. In the future I will upgrade to 200amp service and also upgrade the interior panels, and probably add a panel in the garage.

Separately, I plan to take out the walls in the whole house and add insulation, drywall, replace windows, and fix any issues I see. I’m a DIYer so this will probably be one room at a time.

Question is:
Can I replace the outlets and run Romex® Between the new outlets before upgrading my panel?

For example, I might start with remodeling the unused 2nd bedroom. Chances are the 2nd bedroom is not on its own circuit, and other 2 wire outlets would be upstream from the 2nd bedroom outlets.

Does it cause any harm if I use 3 wire outlets and wiring downstream from 2 wire outlets and breaker?

I’m trying to avoid needing to do the panel until later, and allowing myself to work in bite sized pieces
 

wwhitney

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Does it cause any harm if I use 3 wire outlets and wiring downstream from 2 wire outlets and breaker?
There is a potential failure mode on a 3-wire (with EGC) receptacle circuit segment that is supplied by a 2-wire (without EGC) segment. Namely if you plug two or more pieces of equipment with metal cases and 3 prong cords into the 3-prong outlets on the isolated segment of the circuit with EGC, then if any equipment on that segment suffers a ground to case fault, then all the equipment on the branch circuit will have hot cases.

Best option would be start rewiring each circuit at the (new) panel (supplied by a feeder with EGC), so that any ungrounded (without EGC) segments are downstream of the grounded (with EGC) sections.

2nd best would be to leave the 2 prong receptacles in place until you finish wiring the circuit back to the *new) panel, then change the receptacles to 3 prong once the new EGC is properly connected.

3rd best would be use 3 prong receptacles, leave the EGC disconnected from the receptacle, use a GFCI receptacle at the location closest (logically) to the (new) panel, and go back and hook up all the EGCs once you've extended the new wiring to the panel.

Cheers, Wayne
 

WorthFlorida

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Hi all,...........
Separately, I plan to take out the walls in the whole house and add insulation, drywall, replace windows, and fix any issues I see. I’m a DIYer so this will probably be one room at a time.

Question is:
Can I replace the outlets and run Romex® Between the new outlets before upgrading my panel?
Upgrading any part of your electrical system and house wiring can lead you down to areas you may not be aware of. Upgrading & redoing home wiring is more complicated than most think. Just beware for your safety.

First you need to check your local governess and electrical power company on permitting and how far a DIY'er for this type of upgrade is allowed. Going from 100 to 200 amp will probably need a new meter box change out and a new drop wire to the home. The wire from the meter box to the main panel may also need upgrading. This part is best to hire an electrician to do the permitted work. Many power companies will not allow a connection unless the work has past an electrical inspection by a licensed electrician, sometimes only by those listed on their web site of approved electricians. Not often but you need to ask. A DIY and pass inspection may not pass muster for the power company. From this forum we've learned some areas of Texas it is allowed. California?

Another issue is your earth ground rod. New code in most areas require 2 ground rods placed no less than 6 feet apart and you may need to redo your ground rods with upgraded service.

Another is inside wiring and ground fault and surge protection. Rewiring may require that just about all circuits need to have GFCI receptacles and ARC Fault breakers. https://www.nyeia.com/are-afci-breakers-required-when-changing-a-panel/#:~:text=16 states that AFCI protection,and similar rooms or areas. ARC faults breakers are expensive so to be sure your budget can handle it. If you may need 10 or more ARC breakers and it adds up.

In my opinion you're going in the wrong direction. First upgrade the electrical service, ground rods and breaker panel. In this direction usually the rest of the home will not need upgrading at that time. Then add new wiring and all things will be good when fixing up rooms and new 3 wire outlets.

Another issue you may not be aware of is your sub panels, you'll need both an earth ground wire and neutral wire between the main and sub panels and they can not be connected together at the sub panel. Only at the main panel.

3rd best would be use 3 prong receptacles, leave the EGC disconnected from the receptacle, use a GFCI receptacle at the location closest (logically) to the (new) panel, and go back and hook up all the EGCs once you've extended the new wiring to the panel.

Cheers, Wayne
If you go with your original intent, Waynes 3rd suggestion is the best. Add the three wire but do not connect the green (ground) wire until the panel is upgraded. BTW, AFCI breaker and GFCI will work on a two wire circuit.
 
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wwhitney

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Another issue you may not be aware of is your sub panels, you'll need both an earth ground wire and neutral wire between the main and sub panels and they can NOT be connected together at the sub panel. Only at the main panel.
An important typo--the word NOT was missing above.

Cheers, Wayne
 

TacoFan

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Thank you both, this has been incredibly helpful. I’ll see if I can get my service and panels upgraded first. I am planning to have a licensed electrician do that work. I don’t believe the house has grounding rods of any sort. If I do find myself in a position where I need to replace an outlet downstream from the 2 wire outlets, I’ll be sure to avoid connecting the ground, and also be sure to have a GFCI in place.
 

TacoFan

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Just to confirm I’m understanding, is it ok for me to upgrade the main service and panels without altering the outlets (which are all 2 prong at the moment)? Or do I need to update all the wiring/outlets to be grounded when I update the panels?
 

wwhitney

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When you say "none of the wiring is grounded" I'm going to take that to mean that there are no grounding conductors anywhere.

You can certainly upgrade the service if you simultaneously ensure that you have a proper grounding electrode system and grounding electrode conductor connecting the grounding electrodes to the service neutral (grounded) conductor. The new service can resupply the existing feeders to the existing interior panels.

And you can certainly upgrade the existing interior panels if you simultaneously upgrade the existing feeders to those panels to have a grounding conductor. The new panels can resupply the existing ungrounded (without grounding conductor) branch circuits. Then you can upgrade the branch circuits as you go. When you a branch circuit outlet (meaning receptacle or other load) or more than 6' of the branch circuit, you need to provide AFCI protection for at least modified portion of the branch circuit.

I'm unclear on whether it would be allowed to upgrade the existing panels while leaving them supplied by a feeder without a grounding conductor. But I wouldn't think upgrading the feeder at the same time would be a sequencing challenge.

Cheers, Wayne
 
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