Bus bar Heat distribution

[HooserBrosElec]

Recently my company has started working for a builder and the HVAC company has an electrician who is pulling the ac permits and wires making the circuits up on unit specified breakers. I have been having trouble with some of his work because its sloppy. Most recently he made up the circuits in one of my 40 space panelboards with a 2 pole 60, 40, and 30 at the top with 10 empty spaces than installed a 2 pole 20 followed by a 40 all on one side. Now I have 2 problems with this its sloppy to leave a giant space between the circuits as I have to fill them with single pole breakers and try to fill the panel out to get a cover on and it look professional. The second and most concerning is heat transfer is he not unevenly distributing the heat between top and bottom of the panel? I confronted him with my concerns and said he had a reference to a panel study done that all bus bars are dipped in something that helps to distribute the heat? Of course he didn't follow up with the study. I have briefly looked online but haven't turned anything up. Can anyone point me in the right direction to find the study he is referring to?

 

[suemarkp]

How can you ensure heat is evenly distributed on a bus bar? You have no idea what loads will be on when, or how heavily loaded they will be if feeders. What about solar backfeed breakers at the bottom of a panel and all the loads at the top?? You don't have to fill empty space with single poles, you can leave the panel twist outs in place if not putting a breaker there. In some ways I think it is cleaner to put breakers towards the bottom for wires that come in through the bottom, and put the breakers near the top for ones coming in through the top. In residential panels, the GFCI and AFCI breakers are wider and encroach on the gutter space. I try to put those in space where the neutral bar or ground bar isn't so there is more working room. I reserve the spaces next to the neutral bars for non-GFCI and non-AFCI breakers if possible. That usually puts unused breaker spots in the middle of the panel.

To me, sloppy is things not level, and things all twisted around and overlapping in gutter spaces.

 

[petersonra]

the bus bar is designed to be able to have 100% of its rated current at any place in the bar at any time. so where the CBs are placed just does not matter. in fact, if it was a pass thru panel 100% of the current could pass through. it just would not matter.

as to whether it is aesthetically "better" to do it differently, that is a matter of opinion.

as to some kind of coating, that sounds like BS to me. the bus bar might be plated but that is for corrosion resistance.

if you have a preference as to where the breakers are located, put it in the contract.

 

[hbiss]

I would just have a friendly conversation with this guy and tell him how you would like to see breakers installed. I can't see how it would make any difference to him where they go.

-Hal

 

[Fred B]

It would seem for this application "heating" shouldn't be an issue. If there is legitimate concern of over heating, there are cooling devices that can be added to keep the panel cooler.
Agree the aesthetics of having breakers all over the place might "look bad" to some, but if your concern is heating having the spacing between the larger loads and the others would aid in heat dissipation. AFA that load of single pole being on one side, again not an issue, a normal panel will evenly distribute loads as buss configuration alternates the bus assignment to the individual breakers down the sides, doesn't matter if single phase or 3 phase.
The rating of the buses are, if in a listed product, designed to carry a specific maximum load and will tolerate that load adequately. If the panel is "overloaded" the main breaker is designed to prevent that potential as well (if sized properly for the loads being applied). The electrician will have performed these calculations in determining the panel size.