When Replacing A Breaker Panel, Would You Do this?

Page 3 of 4  
On Thu, 19 Jan 2012 12:18:44 -0500, "Robert Green"

The inspector will be asking for a load calculation if there is any question. You base the service size and panel rating to the connected load, not the number of breakers. Load calculations are part of the permit process on new construction or additions in most places. That usually includes a permit for HVAC or some energy hungry equipment like an electrically heated spa or instant hot water.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

(face
Thanks. I had assumed there was some recognition that electric heat and the A/C would rarely (if ever) be used at the same time. Good to know.
-- Bobby G.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Thu, 19 Jan 2012 19:24:45 -0500, "Robert Green"

They call that non-coincidental loads. If the strip heaters and the A/C compressor are electrically interlocked, you only have to size for the largest one. If your heat pump is wired to allow both, you need to size for both.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

Well in certain commercial situations load balancing is VERY important, you can throw all kids of things out of whack with unbalanced loads...
They make a "super neutral" cable which is used with a 3-pole breaker where there are 3 current carrying conductors of #12 paired up with a #8 neutral conductor... It is used in making up power for cubicle systems... It is like a 2-pole "Edison" circuit on steroids...
~~ Evan
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
news:cd1ea5f4-99f4-4727-93a9-
<stuff snipped>
<<They make a "super neutral" cable which is used with a 3-pole breaker where there are 3 current carrying conductors of #12 paired up with a #8 neutral conductor... It is used in making up power for cubicle systems... It is like a 2-pole "Edison" circuit on steroids...>>
That's interesting. I was told that on two-wire 240VAC circuits, the neutral could always be one gauge under the size of the other two conductors. Does adding a third wire change the dynamics that much?
-- Bobby G.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Thu, 19 Jan 2012 19:27:49 -0500, "Robert Green"

Super Neutral cable is used where you have reactive loads, particularly switching power supplies where the current may lag the voltage. It can set up triplin harmonics in 3 phase line to neutral loads where the neutral load may exceed the individual phase load in some situations. It is not a common problem but when it happens it will burn up the neutral.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Yes, harmonics on the line from electronic equipment can generate non-linear loads which are very tricky to balance...
There are two types of these cables, neutral per phase and over-sized neutral... When you get into type MC cable there are a lot of interesting purpose driven varieties of cable, like heavy gauge feeder cable used for supplying main power to breaker panels, as well as "home run" cable which have as many as 12 #12 conductors to allow for grouping multiple home runs in one cable as opposed to each circuit having its own cable...
~~ Evan
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tue, 17 Jan 2012 21:26:11 -0500, "Robert Green"

42 circuit 100 amp panels are available. That's 630 amps with all slots filled with 15 amp breakers.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 1/17/2012 2:16 PM, Robert Green wrote:

...
...
No; he's talking about the number of conductors in a given size of outlet box. There's a given quota of number vs volume (cu in) in a box in the Code--that's "fill".
It's not that large and almost certainly a shallow outlet box w/ the in/out feed/continuation to next in the chain if one chooses that box to add another branch to, that extra set of wires will push the box over the limit. (While not kosher, it's also probably the place I knowingly push the most, too... :) )
--
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

panel
Ah, gotcha. I'm forever using oversized metal boxes just because in this house, every box seemed to be overstuffed and I use X-10 gear, which takes up more space than the average switch.

Fortunately, after I ripped out the two basement ceilings (installed to cover previous termite damage, In My Humble and Slightly Paranoid Opinion) it became just as easy to install new junction boxes and receptacles. Early on, I broke one wire very short in a wall switch box that ended in excavation and replastering/repainting. That might me very careful about overstuffing boxes.
Thanks for the explanation.
-- Bobby G.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 1/16/2012 12:33 AM, snipped-for-privacy@aol.com wrote:

or NO fuse. the very first rental we took on had the standard MAIN RANGE plus 4 fuse panel. No less than 4 added circuits were hooked to the hot side of the buss. I turned the MR+4 into a disconnect and put a nice 100 A panel next to it and started over.
--
Steve Barker
remove the "not" from my address to email
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Changing the topic a little, but on that episode why did they use 2-8 foot ground rods by the meter outside? I thought only 1 ground rod was sufficient.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Mon, 16 Jan 2012 15:19:48 -0800 (PST), Mikepier

Depends on the ground composition and conductivity. 2 rods is almost standard practice around here
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 1/16/2012 5:19 PM, Mikepier wrote:

two 8' x 5/8" diameter rods at least 6' apart are the minimum required.
--
Steve Barker
remove the "not" from my address to email
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 1/16/2012 5:19 PM, Mikepier wrote:

You can use one rod if the resistance to earth is 25 ohms or less. Meters are expensive and it is easier to use 2 rods. There is no resistance required for 2 rods.
Rods are a crappy earthing electrode. For most new construction a "concrete encased electrode" is required.
--
bud--


Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

It can't if the breaker is sized correcly to the wire size as it's supposed to be. Put a 15 amp breaker on a circuit with 14 gauge wire and you can put as many outlets as you please on it without the wire overheating.
That's one of

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 1/15/2012 1:48 PM, RBM wrote:

I didn't see the episode. Electricians have not been my favorite mechanics on TOH in general (but better than Trethewey doing electrical work).
It is not a problem if a circuit with #14 wire, but #12 at the panel, is connected to a 15A circuit breaker. Occasionally #12 or #10 may be used for voltage drop with smaller wire downstream. In a rewire a #14 ckt might have #12 connecton to the panel. Would seem like a minimal check would be to feel if the wire size matched the breaker, and if the breaker was smaller than the wire use the smaller breaker in the new panel.
There are also anomalies, like you can legitimately have perhaps a 40A breaker on a #10 wire for an air conditioning compressor.
If enforced, the NEC requires meaningful labeling of circuits (408.4-A). ("Lights and receptacles" is not meaningful.) The original panel may have had some of this information (or maybe not).
--
bud--



Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
<stuff snipped>

(-:
panel.
It seemed to me that he was "throwing away" potentially valuable information by not matching the wire to its original breaker.

I've got a very detailed description of the loads (and even outlets) that each circuit powers on my circuit panel door. I update it every time I make a change to the panel. I created it by checking each circuit out individually to see what did and didn't work after I flipped the breakers. I figure it's the least I can do for the next guy to own the house.
-- Bobby G.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Mon, 16 Jan 2012 12:46:04 -0500, "Robert Green"

Most panel directories are so superficial that they are not that useful. When I replaced my panel, I didn't bother to label anything. I wanted a decent panel directory when I was done and I took the time (half a day) to map every circuit by hooking them up one at a time.
As for the 15 vs 20a choice. 99% of the time, if this is not serving the kitchen or the bath and laundry before the 90s you should default to a 15a breaker unless you really know what is down stream. Most builders used 14ga for virtually all of the branch circuits in a home. If it is much older than the late 60s, the kitchen might even be 14ga.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Robert Green wrote:

Inspection sticker?
God, how awful.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

    HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.