When Replacing A Breaker Panel, Would You Do this?

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bedroom
in
It's hard to tell what's happened to a house's electrical system by the time it's over 50 years old. Fortunately, I live in one of the first true "developments" - cookie cutter houses built for office workers flocking to DC for WWII work. There's always someone around who knew what the original system looked like and the 88 year old guy who has been here since the war he says these were 60A total panels with screw-in (4/15A) glass non-safety fuses. I know there were fuses before I got here because I found the color-coded safety types AND a safety-type that was a breaker, not a fuse. That led me to believe they were alway having breaker tripping problems so I was happy to replace two old 15A breakers with newer duals. Not only did I gain a slot, I got new breakers with a known history.
-- Bobby G.
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On Thu, 19 Jan 2012 20:08:28 -0500, "Robert Green"

I grew up in an Allen and Rocks tract house in south east DC. It was built in 1954 and had breakers. That was fairly unusual.
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20A
only
I don't think I said otherwise. What I said was in relation to finding an breaker too large for the circuit. It could easily allow enough current to pass to cause a fire. That's what I found. Someone had put 20A breakers that seemed pretty clear too large for the size wire they were connected to. In that case, a 19.5A load wouldn't trip the breaker but would warm up the in-wall wires pretty well, perhaps melting the insulation and causing an arc. IIRC, that's why arc-fault breakers came into being. (-:
IMHO, to be completely sure, you need to inspect the panel to make sure that all the wires pulled are of the same era if you want to use sizing as your only guide. Even then, every obvious new addition to the panel is suspect, especially if there aren't any matching inspection stickers. There's also no way to tell whether some home electrician added four 150 watt floods to a front door sconce circuit and has severely overloaded the circuit way downstream of the wire at the panel. The older the house, the more likely circuits have been tapped. That's why I mentioned investigating to see which breakers were original to the panel. Tapped and overloaded outside circuits might be fine in the cold weather and heat to the point of failure at the peak of summer.
Ralph, let me ask you what would you think if you found an older panel (50 years old) with cloth covered wire that all looked to be about the same age and gauge. They're hooked up to a mix of half 20A and 15A breakers with the 20A breakers being obviously much newer than any of the 15A breakers. The 20A breakers were all made 10 years after the panel. The 15A breakers have the same manufacture date (almost) as the panel itself. (I'm excluded some of the newer circuits that were obvious late-comers like central A and grounded outlets near windows for window A/C's for the sake of simplicity.)

Wow. Ironically, we may see a time when devices become so efficient that you can live on 40A all over again.
It's interesting how the patterns of electrical usage have changed. Nowadays, since everything has a charger or line cord you can almost never have enough outlets. I don't think I know a single person who doesn't use multiple outlet strips throughout the house. In the modern kitchen, even three 20 amp circuits might not be enough for some households.
-- Bobby G.
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As stated above, the job is to replace the panel, not check out everything in the house. I would look at the size of the wires and put in the correct breakers for the wires leaving the panel. Then report to the home owner what I found. Really report first, then let the home owner make the decision on how much he wanted to spend.
Much the same when you take a car in for tires. If a mechanic finds other issues such as bad breaks or out of alignment, he will change the tires, and report the other issues to the car owner.
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Sorry, but again, not when every circuit except for the dedicated 240 volt appliances were double tapped to the breakers, trying to "decode" what went where when the old panel was packed full of wiring running 25 something circuits off of only 16 breakers...
Totally not worth the time to figure that out -- since the proper replacement of one circuit per breaker when the new panel goes in it is a lot easier to figure out what is on the new circuits by powering them up one at a time...
The old panel wasn't marked but for two or three of the circuits...
It is very nice that everyone here seems to think that tracing every circuit and examining what every connection on it looks like is included in a panel swap and service upgrade but it is not... You will never know what the wiring is like in an existing home looks like without opening every wall or pulling brand new wires to every outlet box, switch box and light fixture and abandoning the old wiring...
You can have a brand new panel with new home runs of brand new wiring but in an old house you will have no clue what is downstream, what the connections are and even where they are located... Too often when an older home is gutted very old knob and tube wiring is found with improper connections tapped into it and junction boxes plastered over...
~~ Evan
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news:80c7a3a0-2073-495d-8f33-
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<<It is very nice that everyone here seems to think that tracing every circuit and examining what every connection on it looks like is included in a panel swap and service upgrade but it is not... You will never know what the wiring is like in an existing home looks like without opening every wall or pulling brand new wires to every outlet box, switch box and light fixture and abandoning the old wiring...>>
I don't think anyone here was advocating tracing every wire and circuit. They were mostly saying it's probably worth it to at least label what wire went to which breakers, especially if there's more than one size of breaker involved. Not doing so saves five minutes and loses information that could actually save time and headache when putting in the new panel for some of the very good reasons people have noted.
-- Bobby G.
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The OP is correct. Just because a heavy gauge wire was used at the panel does NOT mean that all the wiring from that point down to the far end of the circuit is the same heavy gauge. What would happen if there were a smaller gauge wire in the midpoint, and a heavy load placed at the far end of the circuit. The breaker would hold, but the smaller wire in the intermediate point of the chain would act as a fuse (maybe), or maybe set the whole house on fire.
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news:90525220-bd56-48b7-9ace-
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<<The OP is correct. Just because a heavy gauge wire was used at the panel does NOT mean that all the wiring from that point down to the far end of the circuit is the same heavy gauge. What would happen if there were a smaller gauge wire in the midpoint, and a heavy load placed at the far end of the circuit. The breaker would hold, but the smaller wire in the intermediate point of the chain would act as a fuse (maybe), or maybe set the whole house on fire.>>
What I've seen happen far too often is someone tapping into a circuit instead of pulling a new wire from the circuit breaker box. While a light circuit is probably no big deal, adding outlets can easily overload a circuit in a way that causes wires to overheat in the wall. That's one of the reason I mark outlets and fixed lighting loads on the inside door of my circuit panel. It's a Word document I print out on card stock and revise as necessary.
-- Bobby G.
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On Sun, 15 Jan 2012 23:37:26 -0500, "Robert Green"

NFPA somewhat saves you on 15 and 20a circuits with 240.4(D). A 14 gauge wire actually has an ampacity of 20a at 60c rating in 310.16 but they make you put it on a 15a breaker to build in a <80% safety factor. They know users may keep plugging in stuff until the breaker trips, then unplug the clock to see if it will hold I agree if you put a 20a continuous load on a 14 gauge wire it will get warmer than it should but it really should not cause a fire. The one you see in older houses, with fuses, that is really troubling is the 30a fuse on that 14 gauge wire.
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On Mon, 16 Jan 2012 06:44:51 -0500, "Robert Green"

A am not sure the AFCI is detecting series faults reliably yet. They had a hard enough finding intermittent shorting faults. I think we are on AFCI version 4.0 now and there are still plenty of the 1.0 versions out there. It was a product that was rushed into the code and sold to the customer at the point of a government gun, long before they were perfected. The latest AFCI might find a loose connection at a device termination but I wouldn't count on it. The reason I have heard about limiting the stabbers to 14ga wire has more to do with the forces involved in stuffing the device back in the box. You end up bending the wire and deforming the contact. I have never been a fan but as long as they are still listed, I have to hold my nose and approve them.

I am certainly not advising that you should violate 240.4(D) the 14g 15a rule.

Bad workmanship can defeat the safety given by any code rule. ;-)
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wrote in message
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no
faults
The first bunch of GFCI's I bought back in the 80's (I think) were pretty squirrely. The second batch of two I bought just a little later to replace them have been running fine ever since. I think the originals were Slater's and the replacements were Levitons.
I just read the section about arc faults at
http://www.interfire.org/features/electric_wiring_faults.asp
and it explained something that confused me because I did not know there were two, perhaps three kind of arc faults. I did not know the series arc decreases the current flow in the circuit so that a non AFCI breaker cannot respond to the fault. It listed the primary causes of arcs as carbonization of insulation (arc tracking), externally induced ionization of air and short circuits. Gawd, lots of dangers out there I never even knew existed! I know this is probably all old news to you, but I find the various tests they perform to try to get electrical faults to ignite fascinating. I can see why they were anxious to field a safety device that at least tries to detect arc faults. The author claims it's one of the few ways to cause actual ignition:
(1) arcing (2) excessive ohmic heating, without arcing (3) external heating.

That makes sense. I can't count the times I've seen outlets stuffed tighter than the houses they show on "Hoarders." But wouldn't that bent contact likely become a source of an arc fault since it's probably not able to carry as great a current load as an undamaged switch?

From the research at the site above, they may not be listed forever. They seem to be implicated in more than their fair share of home electrical fires. Are outlets that don't use spring clips (just push it in) but hold-down screws (push it in and screw down) both considered back stabs? (That sounds obscene)

wire)
of
which
back-stabs
When you're inspecting outlets and receptacles, what do you look for? I mean what's the most common screw-up made, especially by non-professionals?
-- Bobby G.
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On 1/16/2012 9:47 PM, Robert Green wrote:

No.
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Are the screw down type equal in reliability to the curved wire end under the screw type? They seem to be the best of both worlds - screw-down reliability and (usually) a broad contact area (at least the kind I've seen with the clamping plate).
Thanks for your input!
-- Bobby G.
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On Tue, 17 Jan 2012 11:33:08 -0500, "Robert Green"

Equal or better.
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On Mon, 16 Jan 2012 22:47:04 -0500, "Robert Green"

The AFCI recognizes three different arc faults #1 Faults inside the wall, (v 1.0) #2 Faults from the cord cap to the usage equipment (v.2.0) That is what the original definition of "combination" AFCI and the early AFCIs only detected shorting faults. #3 ... #3 ... Umm (sorry Rick)
The 3d fault is a series fault where you have a loose connection and that was supposed to be detected in V 3,0
There are some revisions within those categories as they improved the product and each manufacturer has their own proprietary method of detecting faults. All AFCIs are not created equal.
Cuttler Hammer also has a GFCI/AFCI breaker that could be handy in one of those places where both are required (IE a wet bar in a bedroom or living room).

The back wired clamping device is not considered a back stab. They are a little more expensive so a guy hitting a price point probably won't use them if they are shaving costs.

I look at box fill, the grounding connection, the way the binding screws are made up and if everything is connected to the right terminal. It is one of those things that you know when you see it.
I am really looking at workmanship first. If this was done by someone who is doing a good job, they usually do a good job everywhere. You just look at a good representitive sample. The boss does not give you time to open every box. That only happens when you see bad workmanship or when you catch someone telling you a lie.
If I had to pick the single thing non-pros do wrong, it would be box fill. They add a circuit to a box that was already close to or at the limit.
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Box fill is the maximum number of conductors permitted for a given box size. In other words, you aren't allowed to put 5lbs of stuff into a 2lb bag.
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wrote:

That's why you put a junction box right outside the panel, combine 4 circuits, and then run one wire to a single breaker in the panel. No concerns about exceeding the box fill specs. ;-)
Please, please note the smiley!
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On Tue, 17 Jan 2012 15:16:36 -0500, "Robert Green"

Panels are always rated for the maximum number of breakers you can use. CTL panels have been in the code since the Johnson administration will actually keep you from putting in too many "mini" or piggy back breakers. Most of the time they will be rated for a full boat of mini/piggies tho. You will see things like 20/40. That means 20 full size slots or 40 dual breakers. The place people get in trouble is when they try to wire a multiwire (shared neutral) circuit to both sides of a piggy back breaker or a pair of minis in the same slot. That overloads the neutral. It should also be noted, there are a couple brands of breakers that allow doubling up circuits on them. Square D is an example.
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A total of 100 amps load on each line of the service is what a 100 amp panel can support... If your circuits are working at capacity then you would only be able to have a total of 100 amps being powered off each buss inside the panel...
You can have MORE breakers in total theoretical load than the main breaker is rated for but if you exceed the main breaker rating it will trip if the actual loads on all the circuits being powered by the panel exceeds 100 amps on either line...
This is why load balancing is important, you want to evenly divide the load to both lines in your panel to ensure you don't experience nuisance tripping of the main circuit breaker...
~~ Evan
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wrote in message
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< A total of 100 amps load on each line of the service is what a 100 amp panel can support... If your circuits are working at capacity then you would only be able to have a total of 100 amps being powered off each buss inside the panel...>
I added about 5 20A circuits to my panel with "dual skinny" breakers which brings the panel to the maximum it's rated for (100A) but they are never used simultaneously and they, in fact, replace the older 15A circuits still wired to the kitchen. I've tracked the maximum usage via the meter and the house never draws much more than 60A, even with all the big loads going at once. The question is - will it pass inspection or does the inpector have a cutoff-point where he won't approve a panel whose individual breakers (face value, not load) to some percent of the total rating of the panel?
<You can have MORE breakers in total theoretical load than the main breaker is rated for but if you exceed the main breaker rating it will trip if the actual loads on all the circuits being powered by the panel exceeds 100 amps on either line...>
That makes sense - what I am trying to determine is whether there's a point at which an inspector will say "that's too many 20A breakers for this panel" even *if* they are all powering very small loads.
<This is why load balancing is important, you want to evenly divide the load to both lines in your panel to ensure you don't experience nuisance tripping of the main circuit breaker...>
Way back when we had to rewire a number of PC's to run off dedicated circuits because they fluttered when the main ventilation blower kicked off. The electrician said it was because the load wasn't balanced.
-- Bobby G.
~~ Evan
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