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New Construction El. Panel Question with pictures.


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You need to tell us if the main breaker in the bottom of that panel is the service disconnect.

If it is the service disconnect, yes, the neutral bus(es) are to be bonded to the panel. Usually, there is a screw that turns in tight to contact the back of the panel, or a solid metal jumper that connects the bus to the back.

What you have done there is unconventional, so whether it is satisfactory will depend on what the authority thinks about it.

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On this particular panel, the screw for the main bonding jumper that John is talking about would go in that small notch at the lower left, just under the left neutral terminal bar. The screw should have been included with the panel, and will have a slightly green color.

Assuming you can't find the screw, the bonding jumper will need to be sized based upon the size of the service entrance cables, probably 4 AWG. I can't be sure from the picture, but it looks like you might have 6 AWG in there now.

Where is the grounding electrode conductor going to connect to this?

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The main breaker at the bottom is sitting there with no conductors connected to it other than the bus bars.

A branch circuit breaker opposite the AFCI's is being used as main disconnect. Unless this breaker is listed for use as main disconnecting means, it should not be used as such.

I don't see any electrode grounding conductors in the panel unless it's in the meter box.

The cable bringing power into the enclosure doesn't look like type SE cable. It should be if it's a main panel. Either that or enclose the SE conductors within conduit.

Curious...why is the panel upside down?

Some jurisdictions don't allow multiple cables within a single connector though most don't bother with making a fuss about it.

Marc

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The main breaker at the bottom is sitting there with no conductors connected to it other than the bus bars.

A branch circuit breaker opposite the AFCI's is being used as main disconnect. Unless this breaker is listed for use as main disconnecting means, it should not be used as such.

I don't see any electrode grounding conductors in the panel unless it's in the meter box.

The cable bringing power into the enclosure doesn't look like type SE cable. It should be if it's a main panel. Either that or enclose the SE conductors within conduit.

Curious...why is the panel upside down?

Some jurisdictions don't allow multiple cables within a single connector though most don't bother with making a fuss about it.

Marc

If it's bottom fed, it is foolish to have the lugs at the top, cleaner installation, less wasted wire, there is no right side unless a main breaker is operated vertically, then a bottom feed would violate NEC requirements, the SQ D main pictured operates side to side so there are no problems w/ it.

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While your panel looks fully functional, and the neutral bonding question has been fully answered, I think your wiring technique will pose future problems for additions.

The AFCI and GFCI breakers would be easier to work around if they did not cover the neutral bus. The lowest (in this case the highest) position is usually best.

Nuetral wires for branch circuits are easiest to deal with in the future if they are wired to the same side of the panel as their associated breakers.

Same with grounds.

Neatest practice is to maintain a one on one relationship between branch circuit breakers and their neutrals and grounds. 1st breaker, left side - first neutral screw, left side - same circuit, etc.

All your grounds and neutrals should go exclusively to the appropriate bus. Mixing them is functional, but a mess to service.

This will make new circuits and troubleshooting much easier once the panel is 'live.'

And of course, do not double wires to neutral or ground bus locations, this is strictly forbidden (code).

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While agreeing with Bob 100% here, it is too late to change most of those things as the wires have already been trimmed to length.

One other T9C thing - the red-black pattern isn't consistent. The two red wires at the top connect to the left bus, and the one at the lower left connects to the right bus.

And this would matter why?

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And this would matter why?

Basically for the same reason Bob posted - problems for someone else down the road.

The conductors are not going to care one bit about the of color their insulation. It is entirely a human factors issue. One reason things follow certain conventions as far as wiring practice is so that the next guy in will understand what is happening. If the next guy is going to add 3-wire circuits he will want to be able to visually identify the pole where each circuit originates, and having them inconsistent creates confusion.

The code used to require that once you picked a certain bus to be red, you had to stay with it throughout the building. The 1968 NEC was the last to say that: "All circuit conductors of the same color shall be connected to the same ungrounded feeder conductor throughout the installation." (210-5). That turned into a non-enforceable fine print note in 1971 and was deleted in 1975. That was the year the lawyers took over, and did all they could to pretend that the NEC is not a design specification. In actual practice, as promoted by IBEW and NECA, this is still the "right" way to do it. I don't know a person working with the tools for a living that would walk away from it with one red wire on one bus and the others on another bus.

So the difference it will make comes down to perception. A journeyman working on this thing in the future will know that this panel was not done by his brethren. That said, I am sure you will all agree that Mr. Velder's work is exemplary for someone not in the electrical trades, and that he has done a far better job wiring this thing than most of the stuff you look at every day. On top of that, he cared enough about getting it right to post it on here. I think he is entitled to know everything we can tell him about what is right and what isn't.

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And this would matter why?

Basically for the same reason Bob posted - problems for someone else down the road.

The conductors are not going to care one bit about the of color their insulation. It is entirely a human factors issue. One reason things follow certain conventions as far as wiring practice is so that the next guy in will understand what is happening...

I don't understand this convention. I'm aware of it and practiced it on 3-phase panels where a color referred to L1, L2 or L3 but for a 120/240 single phase, I don't recall any such thing.

Are you saying that prior to 68', electricians wiring panels used only red wires for one bus and only blk for the other one?

Marc

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And this would matter why?

Basically for the same reason Bob posted - problems for someone else down the road.

The conductors are not going to care one bit about the of color their insulation. It is entirely a human factors issue. One reason things follow certain conventions as far as wiring practice is so that the next guy in will understand what is happening...

I don't understand this convention. I'm aware of it and practiced it on 3-phase panels where a color referred to L1, L2 or L3 but for a 120/240 single phase, I don't recall any such thing.

Are you saying that prior to 68', electricians wiring panels used only red wires for one bus and only blk for the other one?

Marc

Any journeymen I know would look at those connections and immediately know those are MWBC's, wired as I was tought the usual black-red convention, black on top, red on bottom. Or, more accuratley, 120/240 volt circuits.

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Are you saying that prior to 68', electricians wiring panels used only red wires for one bus and only blk for the other one?

Marc

For 3-wire circuits, yes. A multiwire circuit always had to have a red conductor, and the red conductors all had to originate from the same bus. The circuits that were not three wire could use black from either bus if they were part of a cable system. If they were pulled through raceways, then even the non-MWB circuits had to match the color for their bus. This even applied to knob and tube. For 120/208 three phase the convention of black, red, blue was mandated in the code. So was voltage drop. All of that was dropped in 1975.

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just what happened in 1975?

Marc

Yearly Inflation Rate USA9.2%

Year End Close Dow Jones Industrial Average 858

Interest Rates Year End Federal Reserve 7.25%

Average Cost of new house $39,300.00

Average Income per year $14,100.00

Average Monthly Rent $200.00

Cost of a gallon of Gas 44 cents

Average cost new car$4,250.00

Foster Grant Sun Glasses $5.00

Construction of the Trans-Alaska Pipeline System begins

Bill Gates and Paul Allen develop a BASIC program for the Altair 8800

Motorolla obtains patent for the first portable mobile phone

The name "Micro-soft" (for microcomputer software) and Microsoft becomes a registered trademark

NASA launches the Viking 1 planetary probe toward Mars.

US Apollo and Soviet Soyuz 9 spacecraft link up in space and Russian cosmonauts and American astronauts shake hands

BIC launches first disposable Razor

The Microcomputer Altair 8800 is released

Sony introduces Betamax videotapes and Matsushita / JVC introduce VHS

Tuvalu Gains Independence From Great Britain

Mozambique Gains Independence From Portugal

Cray-1, the first commercially developed supercomputer, invented by Seymour Cray

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Thank you for all the input gentlemen. This is my first panel and I am trying to get it as correct and safe as I can. I have learned alot from reading all of your replies.

Another question, I need to install a subpanel for two air conditioners because I don't think I have enough room amp-wise in my 200 amp panel for the two 60 amp and two 30 amp breakers I need for my two 3 ton AC units and air handlers that go with them.

So I was thinking of wiring the panel as if it was also coming straight off the meter instead of from a circuit breaker on my 200 amp panel.

Can I just piggy back wires as shown in my picture below?

subpanel.jpg

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No you cannot. Adding a sub panel does not increase the ampacity of your service. If the sapce is available in the main panel use it for the AC systems. Otherwise, feed the sub from a breaker in the main panel. PS, 3 ton AC's do not require anywhere near 60 amps and air handlers often only require 15 amps.

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No. I wouldn't do that. If that breaker at the bottom is the main disconnecting means, then you need a gutter first. A gutter is an otherwise empty enclosure with the service entrance conductors coming in from the meter box and two sets of feeders going out to the two panels. If done this way, the two panels are both considered main panels and you end up with two main disconnecting means. You can employ this configuration for up to six panels but they all must be installed adjacent to each other in the same room.

The bonding of neutral and grounding conductor takes place within the gutter and of course the gutter enclosure itself must be bonded to earth.

Make sure the service conductors running from the meter box to the gutter are sized appropriately for the electrical loads of the house. There's calculations in the codes that tell you what size is appropriate.

You're a licensed electrician, are you?

Marc

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Hello Joseph

I would think you have plenty of room in your panel to install a breaker that feeds your air conditioners. The available room, in terms of amperage, is based on the total connected load, not the ratings of the breakers. The breakers are never assumed to be simultaneously operating near their maximum capacity.

Tapping into the main feeder lugs would be a very bad thing. The feeders to the AC panel would be an unprotected extension of the service entrance conductors, without any form of overcurrent protection, and the lugs themselves would not be rated for two conductors.

A couple of 3-ton air conditioning units is not all that large a load. The instructions might be calling for a certain maximum size overcurrent protection device to handle the inrush current that occurs when they start up, and that only lasts for about 1/10 of a second. During normal operation, I doubt the two of them combined are going to draw more than 40 amps.

There are lots of other ways to do it. You could run individual branch circuits from this service panel to the AC units, or you could install a $ubpanel. Either way, you are going to end up needing disconnects within sight of the AC units. If you are dealing with an AC sub, I suggest you ask them for their preference. As to other choices of how to do it, please realize you are getting close here to asking an internet forum for design advice. None of us are really going to be comfortable providing that, though I do applaud the diligence you are applying to the planning stages of the project.

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When I read the amperage drawn at start up it scared me and I started thinking "what if, they start up simultaneously and they trip the main breaker and how often will this happen?"

This is only a typical 3 bdrm house 1,800 square feet under roof. I'm sure

I'll be ok just adding the AC breakers to the main panel as Mr. Hansen has suggested.

I'll post more pictures when I finish wiring it up.

Thanks again!

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I've seen many houses with a 200 amp service and 4 central AC systems, some totaling over 10 tons of cooling power and the main breaker holds without problems.

Modern condenser units have delay timers that delay the re-start of the condenser once power is restored after an interruption. Never seen them on one house all timed the exact same number of seconds.

Marc

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