Tips for Your Electrical Panels!

Tip #11: DIN Rail and Terminal Blocks

The automation industry has standardized on the 35mm DIN rail for mounting electrical components. From terminal blocks to network switches, you can find almost anything designed to snap on these rails (similar to Uni-Strut). I recommend sticking with these kinds of components in your design since they are easy to install and remove, and they are typically designed to be as narrow as possible to save precious panel space.

I also strongly recommend using terminal blocks for your panel internal connection, especially where you intend to make connections to field devices. These can be had from AutomationDirect for as little as $0.20 each and give you a clean, centrally located point to land your wires. Please don’t ever use those “ice-cubes”, wire nuts, or God-forbid solder your connections.

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Excellent series of tips, Macardoso! Thank you so much for sharing. Electrical is my primary weakness and the more I learn the better and safer things will get.
 
Ooooooooo....

I was an electronics tech in the Navy for 22 years, and have worked around electronic/electrical/electro-mechanical equipment pretty much all my working life.

My last really technical job was working in a fish cannery with a ton of PLC-controlled equipment, some of it built in-house for a specific task. I had the pleasure of building and/or rebuilding a few panels and I REALLY enjoyed the process. I used every tip you listed except the riv-nuts and would have used them as well if I could have gotten management to spring for the supplies. Throw in some hydraulic and pneumatic control interfaces and it's about as much fun as you can have and get paid for it!

Yeah, I know, I'm a little strange... :oops: :D
 
Wish you lived next door and had an occasional taste for home distilled corn squeezins. Everyone would come out happier.

We have a machine shop at the end of the road where 3-phase can't be had. As a result, we have a lash-up of three home-built 5hp rotary converters, a couple of VFDs and two maxed out 200-amp service panels. That everything electrical works is evidence we try diligently, but it ain't pretty.

jack vines

BTW, since we have a couple of experts here, what are the options for feeding multiple panels from one incoming line? Right now, we're feeding a 50-amp sub-panel with four circuit breakers off a 50-amp breaker in one of the 200-amp panels. What would the proper junction box look like to take the incoming 220-volt line feed off the transformer and split it into separate lines to four separate panels; two 200-amp and two 50-amp? Just seems silly to waste panel space and seems even sillier to feed a breaker from a breaker.

j.v.
 
Packard V8 said:
Wish you lived next door and had an occasional taste for home distilled corn squeezins. Everyone would come out happier.
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Well now that sounds fun! Too bad you're a little more than a short hike away!

Packard V8 said:
BTW, since we have a couple of experts here, what are the options for feeding multiple panels from one incoming line? Right now, we're feeding a 50-amp sub-panel with four circuit breakers off a 50-amp breaker in one of the 200-amp panels. What would the proper junction box look like to take the incoming 220-volt line feed off the transformer and split it into separate lines to four separate panels; two 200-amp and two 50-amp? Just seems silly to waste panel space and seems even sillier to feed a breaker from a breaker.
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I will start with a disclaimer that I am not an electrician and I am not an expert on home electrical code. With that said, you'd definitely want to have one main breaker for the incoming feed (200A) which would distribute out to smaller breakers in that main panel. You would install a breaker in that panel which would be large enough to cover the panel you wish to distribute out to. You would then run wires from that distribution breaker out to your other panel. I have a feeling this is how it is done since your main breaker plugs into the big copper bus rails in the breaker box.

In industry, it is not unusual to have several large loads needing to be powered by one utility. This would be done by installing one large set of fuses (or a breaker) at the utility entrance to the panel and using the NEC tap rule to connect multiple smaller breakers (sized for each individual load) off of the main breaker. These are usually sized or timed to make sure they trip in the correct sequence (smallest breaker first). Real electrical panels often have many layers (branches) of circuit protection.
 
Tip #12: Cable Entry

Your electrical panel is going to need a way to get wires into and out of the enclosure. For power wiring and short cables which are easy to disconnect at the other end, I recommend using cable glands (cord grips) these are water tight bulkhead connections which mount in a round hole. When you are connecting to long cables or ones that would be easiest to disconnect at your panel, I recommend looking at connectors. My personal favorite are M12 bulkheads. These take up very little space on the side of your panel and come in 4 and 5 pin (also 7, 12, 22, and more) flavors. AutomationDirect seems to have the best price on these. They screw together for a very secure and water tight connection.

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https://www.automationdirect.com/ad...ns/micro_(m12)_receptacles/7231-13541-9710050

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For ethernet cables, USB, and similar pluggable media, look on eBay for bulkhead connectors that mount in a round hole. This way you can use a UniBit or step drill to cut it out.

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If you need to make a lot of I/O connections and want a super robust connector (and have very deep pockets), look at MIL-SPEC-D38999 TVIII connectors from Amphenol and others. They are kinda crazy on price but I have never felt quality quite like these.

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Tip #13: Disconnect Switch and Operators

It is nice to have a power disconnect switch mounted to the door of your enclosure. AutomationDirect sells some rather inexpensive options for this. These usually have a switch body mounted on the subpanel, a handle on the door, and a bar that connects them. These lock the door closed when the power is on, but can usually be defeated. These are my favorite for home use:

https://www.automationdirect.com/ad.../socomec_ul_508_rated_non-fusible_disconnects

Be warned... It can be a bit tricky to line up the handle on the door so that it catches the bar correctly. Be careful installing it or risk ruining your enclosure (personal experiences here guys :rolleyes:). These should always go on the edge of the door opposite the hinge.
 
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