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Small Cabin Forum / Cabin Construction / Running cabin feeder off 200amp panel
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jovol
Member
# Posted: 8 Dec 2021 21:44
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Heya, I'm in the process of figuring out how to wire a park model cabin to my existing 200amp service. The crux right now is sizing my feeder wire appropriately. I currently have 2-2-2-4 MHF running to a subpanel 150' from the main panel, which feeds a 50amp camper outlet. My options are to either use this subpanel to feed the cabin (40' run from subpanel to cabin, totalling ~190'), or run a new line from the main panel to the cabin (~135' run).

The cabin currently has a 60amp main breaker. Appliances include electric stove, wall unit AC/heat pump, electric water heater, lights and outlets. I plan on changing the stove to a gas stove, and I'll be predominantly using a wood stove for heat. I want to add a dishwasher and compact laundry machine/dryer. I imagine I'll swap the main breaker to 100amp when all is said and done.

So.... should I just run the cabin off the 2-2-2-4 mhf via the subpanel, or lay new cable directly from the main breaker? If so, should I run 2-2-2-4 MHF ($1.78/ft), or alternatively lowes has a screaming deal on 4/0-4/0-2/0 URD (1.37/ft, +$0.35/ft for 4AWG AL USE-2... $1.72/ft), and I can add a 4 awg ground separately.

Kinda separate from the gauge question is how to wire the main breaker panel for this. I have a Square D homelite SO2040VP which does not have feed through lugs, but they do sell Square D HOML2125 125amp sub feed lugs for about $50, which looks like it uses two breaker slots to feed a subpanel without protection. From what I can tell it can fit up to 300mcm, which includes 4/0. Is this the right way to go about it?

Brettny
Member
# Posted: 9 Dec 2021 06:03
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I believe you can run a sub pannel (your cabin) off a sub pannel (location of your 50a RV plug)..but check local codes. If you can I would do it this way, it will save you some money on wire. Just use the direct burrial MHF stuff.

WILL1E
Moderator
# Posted: 9 Dec 2021 08:11
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Curious to the benefit of a feed through lug vs. just putting in a breaker and then feeding the new sub from that breaker? Is it just to avoid having the new sub on a breaker?

toyota_mdt_tech
Member
# Posted: 9 Dec 2021 08:43
Reply 


I know the rule of thumb is a main shut off is also required in the sub panel, unless you can open all breakers with one hand. So they rely on a main or fed via a breaker, then the breaker becomes the main. The feed or inlet breaker MUST be anchored down with a screw.

Also, you do want 4 wires to that sub panel and make sure your neutrals and grounds are NOT bonded at the sub panel. You may have to add a few more ground buss bars, you can buy those in the electrical section.

jovol
Member
# Posted: 9 Dec 2021 09:27
Reply 


Quoting: WILL1E
Curious to the benefit of a feed through lug vs. just putting in a breaker and then feeding the new sub from that breaker?

It's a combo of things. The 125A sub-feed lug attachment can handle 4/0 wire, only costs $50, and I don't need circuit protection since the cabin has a main feed circuit breaker. (The main panel is also protected with a 200amp breaker). The 125A circuit breaker is out-of-stock everywhere and costs minimum $85 from lowes, and can only handle 2/0 wire.

Quoting: toyota_mdt_tech
Also, you do want 4 wires to that sub panel and make sure your neutrals and grounds are NOT bonded at the sub panel. You may have to add a few more ground buss bars, you can buy those in the electrical section.

All clear on that. Already have separate ground bus bar at the current subpanel. Cabin has it's own breaker box with unbonded neutral/ground.

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