Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Stephen Swaffer]

The only question I have, is with all the amazing wiring stories over the years, if you hire a real electrician, how would he know where to start?

I know the question is rhetorical to an extent-sight unseen, my approach has always been to address the service first.  Just like there is no sense remodeling on a bad foundation, you can't address wiring issues without a good service.

Typically, there is a major issue that has triggered the call-of course it gets fixed next-or maybe first.

Next I address the heavy current draw appliances-AC unit(s), ovens, water heaters, electric heat.

Next would be kitchen and bath circuits-again high current draw typically.

Then JR is correct -you go until the customer says enough is enough-sometimes you go a littler farther on the same money so you can sleep at night if they really can't afford it.

I already like the guy JR is talking to-sounds like he is approaching it the way I would-just do what the customer is wanting addressed and maybe mention any obvious things that might come up.  It can be a real pain to correct wiring into an old fuse box-I have only seen a few that had enough circuits for a modern home, so they are typically wired in non-code compliant ways (usually there is a violation of the manufacturers specs on the number of wires under a screw-part of the UL listing).  Even if it is wired that way when I get there, if I put it back with new wire, now I own the liability.  The only reasonable fix is a service upgrade.

[frank kayser]

I know the question is rhetorical to an extent-sight unseen, my approach has always been to address the service first.  Just like there is no sense remodeling on a bad foundation, you can't address wiring issues without a good service.

Typically, there is a major issue that has triggered the call-of course it gets fixed next-or maybe first.

Next I address the heavy current draw appliances-AC unit(s), ovens, water heaters, electric heat.

Next would be kitchen and bath circuits-again high current draw typically.

Then JR is correct -you go until the customer says enough is enough-sometimes you go a littler farther on the same money so you can sleep at night if they really can't afford it.

I already like the guy JR is talking to-sounds like he is approaching it the way I would-just do what the customer is wanting addressed and maybe mention any obvious things that might come up.  It can be a real pain to correct wiring into an old fuse box-I have only seen a few that had enough circuits for a modern home, so they are typically wired in non-code compliant ways (usually there is a violation of the manufacturers specs on the number of wires under a screw-part of the UL listing).  Even if it is wired that way when I get there, if I put it back with new wire, now I own the liability.  The only reasonable fix is a service upgrade.

Just what I needed... a smart answer to a smart-ass comment.  Will you guys ever stop being nice and so darn helpful?  /sarc


Seriously, it is a clean, well thought out, approach.  A good thing to put away in my mental toolbox.


Happy new year to all you helpful folks!


frank

[John Roberts {JR}]

I am starting to second guess my interest in putting in a new 4 wire drop for my replacement wall oven. I just checked the old wiring and found that it used 3 wires with the oven ground bootlegged to the white neutral.

The new oven is on order and specs out at 240VAC/15.5A max, with a recommended 20A breaker.  I suspect the existing (3 wire power drop, and breaker) is adequate for the current carrying demands of the new replacement oven.

If this was new construction or even a remodel, code would require a new 4 wire drop but I suspect I am within normal practice to use the existing drop with the bootleg ground.

At a minimum I plan to have the electrician add a junction box to protect the new connections. Right now there are just loose wires hanging out in the back of a lower kitchen cupboard (with black tape wrapped around the connections).

My dominant "cheap" gene is yelling in my ear to not fix something that isn't broken.

JR

[Stephen Swaffer]

Is this 3 individual wires, or 3 wires in a cable?  My rule of thumb in recommending to replace is if it is individual wires , or if it is the "cloth" type insulation.  If it is a cable with the newer "PVC" insulation and that insulation is still flexible I usually feel OK with it.  Brittle insulation is a sign of overheating.

Undisturbed "knob and tube" wiring that is in uninsulated walls is usually OK-but it is not acceptable if insulation has been added.

Three wires for ovens/cooktops had been the norm for a very long time.  My personal suspicion is that the main reason for the rule change was to make code consistent.  One section prohibited current on a ground-another section allowed it.  Then you have the quandry in some new and remodel's of the panel actually being a subpanel because you have a disconnect outside (often code mandated.)  A subpanel has it's ground's and neutral's separated-so where do you land the third wire in a 3 wire range circuit-ground or neutral?  Requiring a 4th wire makes this easy.

[John Roberts {JR}]

Is this 3 individual wires, or 3 wires in a cable?  My rule of thumb in recommending to replace is if it is individual wires , or if it is the "cloth" type insulation.  If it is a cable with the newer "PVC" insulation and that insulation is still flexible I usually feel OK with it.  Brittle insulation is a sign of overheating.

Thanx... It is old fabric (dark red) covered cable but looks like PVC insulation on the individual wires inside, so wires look similar to what you'd find inside romex or BX but cheaper (older) red fabric covered outer jacket (no discoloration).

There are hundreds of feet of the stuff all over the house (mostly in the attic), I have electric in wall heaters in most rooms.

I expect the wire is OK for 15A max.

Undisturbed "knob and tube" wiring that is in uninsulated walls is usually OK-but it is not acceptable if insulation has been added.

Three wires for ovens/cooktops had been the norm for a very long time.  My personal suspicion is that the main reason for the rule change was to make code consistent.

+1 makes sense... a bootleg ground when the neutral is not really carrying heavy current is less problematic.

One section prohibited current on a ground-another section allowed it.  Then you have the quandry in some new and remodel's of the panel actually being a subpanel because you have a disconnect outside (often code mandated.)  A subpanel has it's ground's and neutral's separated-so where do you land the third wire in a 3 wire range circuit-ground or neutral?  Requiring a 4th wire makes this easy.

Yup, never simple,,, but I am happy seeing three wires in the oven power drop. My hot water power drop*** only had two conductors visible (neutral lead probably trimmed back). If the oven drop only had two wires, I would go for a new power drop, but three wires allows for a typical bootleg neutral-ground bond.

JR

*** I did run a separate ground wire bond for my new hot water heater from chassis ground back to the panel.

[Jonathan Johnson]

I expect the wire is OK for 15A max. +1 makes sense... a bootleg ground when the neutral is not really carrying heavy current is less problematic. Yup, never simple,,, but I am happy seeing three wires in the oven power drop. My hot water power drop*** only had two conductors visible (neutral lead probably trimmed back). If the oven drop only had two wires, I would go for a new power drop, but three wires allows for a typical bootleg neutral-ground bond.

JR

*** I did run a separate ground wire bond for my new hot water heater from chassis ground back to the panel.

For what it's worth, ranges and ovens, even if they use 240V for the elements, often use 120V for the controls and lights. That requires a neutral.

Ordinary electric tank-style water heaters, on the other hand, only use 240V. (I don't know if the fancy-schmancy ones use 120V controls.) So they typically won't have a neutral. In your case, it may have been wired with early Romex that didn't have a ground (just two insulated wires); the white* wire was used as one of the hots. I've seen quite a bit of that stuff in older houses.

*The stuff is so old that the white wire is no longer white. It's typical for the conductor insulation to be rubber (now brittle) with a fabric overbraid. The overbraid was typically white cotton, with colored threads in the overbraid to identify the conductors. So the "hot" wire overbraid would be white with a couple of black threads. If you had 3-wire cable, then one of the wires would have red threads. The outer jacket was an asphalt-impregnated cotton overbraid, with a paper liner separating the wires and outer jacket. Over time, volatiles from the rubber or the asphalt would leach into the conductor overbraid, discoloring it and making it difficult to identify the colors.

[John Roberts {JR}]

For what it's worth, ranges and ovens, even if they use 240V for the elements, often use 120V for the controls and lights. That requires a neutral.

I recall seeing 120V outlets on electric stoves, not my current one.

Coincidentally a musician was electrocuted (killed not just shocked) when he got between two properly ground bonded (3-wire) Peavey guitar amps, with one plugged into a RPBG outlet, and the other an electric stove outlet.

I ASSumed the stove outlet was properly grounded but in light of the apparent common practice this stove outlet was likely bootleg grounded to neutral. 

Ordinary electric tank-style water heaters, on the other hand, only use 240V. (I don't know if the fancy-schmancy ones use 120V controls.) So they typically won't have a neutral. In your case, it may have been wired with early Romex that didn't have a ground (just two insulated wires); the white* wire was used as one of the hots. I've seen quite a bit of that stuff in older houses.

My recollection is that the water heater leads were red and black, so consistent with a 3 conductor cable that had the (white) neutral clipped.

*The stuff is so old that the white wire is no longer white. It's typical for the conductor insulation to be rubber (now brittle) with a fabric overbraid. The overbraid was typically white cotton, with colored threads in the overbraid to identify the conductors. So the "hot" wire overbraid would be white with a couple of black threads. If you had 3-wire cable, then one of the wires would have red threads. The outer jacket was an asphalt-impregnated cotton overbraid, with a paper liner separating the wires and outer jacket. Over time, volatiles from the rubber or the asphalt would leach into the conductor overbraid, discoloring it and making it difficult to identify the colors.

Perhaps you are thinking even older, or different vendor than my house.

From the last time I was up in my attic there looked like a lot of the same cables used all around the house, at least all the 240V drops (in wall electric heat so plenty).

I estimate my house was built in 50s-60s from talking with neighbors who grew up here. I recall (modern?) romex from back around that time while I was growing up in NJ (watching my older brothers do wiring around the house), but I suspect my present house was built using the cheapest raw materials they could get.

I already have replaced a cheap (cardboard?) sewer pipe that collapsed, and cheap water main (galvanized steel) that rusted through and leaked. I have no reason to expect premium wire was used.

The wires inside the fabric jacket appear to use PVC(?) insulation that is in decent condition. If the wire insulation looked flaky I would replace it, but it doesn't. My concern is mainly the workmanship on the electrical wiring that leaves much to be desired. The current oven hook up is just the BX lead coming from the oven and fabric covered drop from breaker panel, hanging down under the oven in the back of a cupboard. The individual wires are hanging out in the open, twisted together and covered with black tape.....

A few years ago I had a burner on my stove top not reaching full heat because of a loose wire connection (now that is a little scary).

Again thanks for helping me refine my decision. I feel OK about the wire unless my electrician talks me out of it. I plan to have him revisit the stove wiring too.

He also does plumbing work so is probably still busy dealing the the recent hard freeze cold snap. 

JR

[John Roberts {JR}]

Well my friendly electrician still hasn't returned my recent calls.  I have the new wall oven sitting on my kitchen floor and can wire it in myself, if it comes to that.

A new curiosity, I went to cut the breaker for the wall oven and it turns out to be the same breaker as my fuse box and all interior outlets. I hoped I could cut power to just the oven and remove the old one at my leisure, without powering down my entire house.    I may have to do this in stages. 

Looks like a separate breaker for hot water heater, and dryer gets its own feed, leaving 4 breakers for everything else. Five in wall resistance heaters, and a 240V outlet for my in wall air conditioner so clearly several drops are doubled up on the breakers.

I got the door off the old oven so can probably wrestle it out by myself.... that door was pretty heavy... I expect the new one will be similar weight(?). New oven was 110# shipping weight. Time to RTFM. 

JR

PS: I've noted this before but there is a significant difference in sensitivity for my (very cheap) NCVT between picking up 120V drops and 240V  drops. I suspect some kind of first order cancellation of 240V from the two 120V legs swinging in opposite directions.

[Lyle Williams]

Kill power to the whole house.  Don't assume that you fully understand old and uninspectable wiring.

[Stephen Swaffer]

Is there a pull out fuse block in the fuse panel for the wall oven?  The typical fuse panel had 2 pull out blocks- one was the main over current protection, the other usually the oven then 4 ( or more if expansion blocks were used ) edsion type fuses for the 120 vac circuits.  Sometimes stuff got wired directly to the feed thru lugs so the only shut off is the main.