We are installing a 200 amp outdoor service panel (specifically, this one) and want to run 3 subpanels (1x100amp for the pole barn/workshop and 2x60amp for other locations on the farm). I was planning on running 2-2-2-4 Dyke Quadruplex Aluminum Conductor 600V URD wire as the main feed for each of these sub-panels because I found a great deal on it. Each run to the sub-panel will be directly buried to each of the 3 different locations (see attached sat image)

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My Questions:

Is this wire sufficient to power each of these sub-panels using separate breakers (no feed-thru)?Is this wire overkill for what I am trying to accomplish?How should I go about hooking larger wire to breakers in the main box, or will this 2-2-2-4 wire fit into 100 or 60amp breakers without modification or tap lugs?Am I missing anything?

Any help or advice would be massively appreciated.

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edited Apr 27 "20 at 9:11
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Michael Karas♦
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asked Apr 27 "20 at 6:57
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Stop. You"re making the classic novice mistake.

I"m referring to sizing the subpanels.

Ever bought tires? They come in different speed ratings. Have you ever gone "My truck has never gone faster than 85 mph, therefore I can"t use an HR rated tire"? Of course not. The fact that it"s good for 112 mph, you see that as safety margin. Am I right?

Well, panels work exactly the same way. Even if you never plan to pull more than 60A, a 100A panel is better, and a 200A panel is better still.

Remember. The size of the subpanel does not decide the load. That"s decided by the feed breaker in the main panel. The "main breaker" in the subpanel is nothing but a disconnect switch.

Your actual main panel has a 60A breaker feeding a 2-2-2-4. This goes to a 200A subpanel. Legit? YES. The subpanel has its own "main" breaker of 200A. Legit? YES. That breaker is nothing but a local disconnect switch. What is the rating of the subpanel? 60A. Because that"s decided by the feed breaker. Is the panel running at redline? No, not nearly, it"s well in its safety zone. And that"s good, because it"s outdoors.

Some people want the subpanel"s local main breaker to be same size as the feed breaker. Their dream is that this local breaker will trip first, and save them a walk. Nope! That trick never works! But I"ll come back to that.

And don"t be chintzing out on panels anyway.

This one person thought the $20 6-space panel was a great bargain. #1 guess what, you need a main disconnect. Boom 2 spaces gone that the person did not expect to lose. Just for one each 120V and 240V utility sockets, the person now has 1 space left. They wanted a hot tub, well that takes 2 spaces, and they"re out of space. Can"t use double-stuffs because 2020 NEC pretty much outlaws them. That person is painted into a corner and must now install an 8-space, and will need to go 12-space for the next thing. How many times are you going to replace panels?

I put the person into a 24-space panel with a main breaker and with $20 worth of bonus breakers, for $70. So $30 more (net) and a vastly superior panel with plenty of expansion room. $30? That"s a takeout pizza.

Spaces are cheap. Redoing work is expensive. Everytime you change a panel you risk damaging wire - and then you"re really in trouble.

See more: 17) Identify The Number Of Bonding Pairs And Lone Pairs Of Electrons In Br2.

If it was hundreds of dollars of wire, sure. But c"mon. A pizza? Skip it and enjoy an installation with expansion room. You"ll thank yourself later.

If I were paying for the panels - and I do pay for most of the panels I install - I would use a 12-space main-lug at the remote sites and a 30-space at the shop. Space not circuit... circuits mean nothing anymore.

The wire size

The 2-2-2-4 Al is a perfectly fine wire size for the runs you have "60A". Feel free to breaker those at 80A at the main, since that is allowed on 2-2-2-4 of any length (unless the length carries it into Canada, then no). "Nanny breakers" (downbreakering to a 60A to protect yourself from "voltage drop" ooga-booga) are not required in the USA or El NEC countries.

For the 100A run, you can"t breaker the 2-2-2-4 at 100A, I"m sorry. You need to use at least #1 aluminum. Now, if you actually needed 100A, you"d be required to breaker for 125% of that, or 125A obviously. But let"s say you actually need 80A, so you breaker for 100A.

Never calculate voltage drop on breaker trip. Either calculate it on expected load, or on 80% of breaker trip since that is the max you"re allowed to plan to load. So that means we"re calculating your workshop run at 80A.

#1 wire gives 4.44% drop at 80A1/0 wire gives 3.82% drop2/0 wire gives 2.98% drop

So pick your poison.

You do need a "main breaker" (well, disconnect switch) at EACH subpanel

"6-space guy" got blindsided by needing a "main" breaker as a disconnect switch. In a 6-space panel, "main breakers" are placed in regular breaker positions and backfeed. Suddenly 2 of 6 spaces are gone - whoops!

However, you can use that same backfeeding trick (hopefully with a larger panel, say a 12-space) -- fit a plain common breaker at the top left, label it "Main Disconnect", apply a Tie-Down Kit, and feed the panel there.

This means you"re using the same kind of branch circuit breaker that is supplying the panel at the other end. So that makes "trips locally first" at least a 50/50 proposition. (if the other one always trips first, swap them; that"s just manufacturing tolerances.) You can help that even further by making the local breaker smaller. Say you use an 80A feed breaker at the main panel, and a 60A or even 30A "main breaker" in the sub. It"s a "nanny breaker", sure, but it"s helping you save a long walk.