# Inverter wire distance



## jjh81 (Aug 17, 2010)

So I have searched and searched for an answer to this question. But here goes I have a 2700 watt solar array using a midnight classic charge controller and a magnum ms4048 240v inverter. I have been told by my building dept that my batts cannot be in the house so I need to move my equipment to a shed. It will be a minimum of a 100ft run. Can this be done? The panels can be placed within about 15 to 20 ft of the solar equipment but the run from the shed to the house like I said will be about 100 to maybe 120 ft. Any help would be great.


----------



## TnAndy (Sep 15, 2005)

Little more info required. Are you running the 240vAC inverter output that distance ? Very little problem if so.....simply gauge the wire to meet your amperage + some for voltage drop....which will be minimal. Not much loss on 240v AC......low voltage DC is different story.


----------



## Steve_S (Feb 25, 2015)

On the Building Dept. Why would they tell you to keep the batteries out ? If they are FLA and contained within an "approved" vented battery box there should really be no issue, if they are LifePO4 / Lithium or other then it should be irrelevant. 

On the Classic & Outback, they should stay as close to the battery bank as possible as you don't want long runs of DC cable. Panels to Charger Controller is a different issue. As for Cable Sizing, my first system had a 24VDC / 3Kw Inverter/Charger and that was fed with 2/0 Fine Wire Welding cable. I upgraded to a Samlex 4024 and upped the cables to 4/0. The run is 8' from battery to E-Panel then 4' from E-Panel to Inverter. Again I'm using Excellene (sp?) Welding Cable. You are far better running AC for distance via 3 Wire from your inverter to you input AC Panel, it will cost you a LOT less and much less hassle with inspectors etc because they are all comfortable with that. Far too many still cannot wrap their brains around Solar Systems let alone ones with battery banks & DC gear they aren't used to. The gauge of the cable also depends on the distance you have between your battery bank & DC Panel & Inverter. A Lesson Learned for me, is that I should have went with the 4/0 Cables right from the get go, as having to buy new cables again wasn't cheap.

Here is a Link to my system info (diag's & pics) I posted @ Midnite. http://midniteftp.com/forum/index.php?topic=4643.0
Hope it helps.

I have this installed in a separate Power / Pump House 75' from my home, the Solar Panels are Fixed Mounted off the side of my Sea Can 40' from the Pump House. I', running 10/2 NMWU in conduit from combiner @ the panels to powerhouse. AC from the powerhouse to home runs via 6/3 NMWU in conduits (but I am only using 120V so one is dead headed but in reserve "just in case"). You may also find this useful as there is wire size calculators etc: http://www.freesunpower.com/wires_cables.php


----------



## jjh81 (Aug 17, 2010)

The long run is the 240v ac run from the inverter to the sub panel for the house. Solar panels are within 15 feet of charge controller batteries are within about 5 feet of inverter.


----------



## TnAndy (Sep 15, 2005)

OK....I assume the 4048 means a 4,000w output, the 48 is for the DC supply ? IF that is the case, 4,000/240 =16amp......#12 wire would carry it, but too be safe (and for little extra money), use 10ga.


----------



## jjh81 (Aug 17, 2010)

TnAndy said:


> OK....I assume the 4048 means a 4,000w output, the 48 is for the DC supply ? IF that is the case, 4,000/240 =16amp......#12 wire would carry it, but too be safe (and for little extra money), use 10ga.


Yes 4000w 48v dc It would do a 100 to 150 ft maybe longer run no issues?


----------



## TnAndy (Sep 15, 2005)

jjh81 said:


> Yes 4000w 48v dc It would do a 100 to 150 ft maybe longer run no issues?


Yes....running 240vAC that distance is not an issue. That's the advantage of higher voltage AC....the reason Westinghouse won over Edison  (Google it)


----------



## secondhandacres (Nov 6, 2017)

In my area 100amp direct bury aluminum service wire is cheaper than 10gage like you need. I would run 100amp wire and not worry about voltage drop across that run of wire. Just my 2cents


----------



## TnAndy (Sep 15, 2005)

Not here. 2-2-2-4 100amp rated aluminum is $1.40/ft 10-2 UF copper is $1.19. Other thing to consider is the lug size on either end, in terms of size wire it will accept.


----------



## secondhandacres (Nov 6, 2017)

That’s true, lug size could be a problem. Need to take into account conduit cost as well, direct bury is just that. Dig a hole through it in cover it over. I assume the 10-2 copper isn’t direct bury. Copper wire is a much better conductor than the aluminum I was talking about too


----------



## TnAndy (Sep 15, 2005)

UF wire is approved for direct burial. Actually found an online place where 10/2 is 78 cents/foot.

https://www.wireandcableyourway.com/uf-b-wire-direct-burial/


----------



## Hullspeed (Oct 29, 2018)

Here's a video where I ran 240v over 600 feet (2-2-2-4 gauge) and then I later converted that wire to a DC run from the panels to the inverter. It works perfectly; but if I were doing it over I would add more wires for ground bonding.


----------



## JeepHammer (May 12, 2015)

jjh81 said:


> So I have searched and searched for an answer to this question. But here goes I have a 2700 watt solar array using a midnight classic charge controller and a magnum ms4048 240v inverter. I have been told by my building dept that my batts cannot be in the house so I need to move my equipment to a shed. It will be a minimum of a 100ft run. Can this be done? The panels can be placed within about 15 to 20 ft of the solar equipment but the run from the shed to the house like I said will be about 100 to maybe 120 ft. Any help would be great.


Midnight Solar made several versions of 4048,
4,000 watt inverter, 48 Volt DC output.
240 Volt AC output, which means two 110vac Hot legs and a Neutral leg from inverter to house.

4,000 watts ÷ 240 volts = 16.66 amps.
16.66 amps ÷ 2 ea. 110volt hot legs = 8.33 amps per conductor.

16 AWG (16 Ga.) Per conductor would handle what you have.
16 AWG copper will handle 11.3 amps per conductor without heating.

Keep in mind, inverters have a 'Surge' (overload) available, and you need to cover 100 feet or more. While AC pushes through longer runs of wire better than DC (less electrical resistance losses), 100+ feet needs to be addressed with a conductor size increase.

I personally would go with a 240 vac 10 AWG (10 Ga) or what's called a 10/3 wire.
Due to the volume of 10/3 cable made, it's a little cheaper.
The capacity of 10 Ga. is 32.5 Amps per conductor without heating, so this will let you upgrade/upsize your inverter in the future...

The second argument for 10 AWG, a lot of codes won't allow anything smaller simply because so many breaker boxes aren't built for anything smaller.
(I didn't say you couldn't install anything smaller, they simply weren't code certified for anything smaller)

I personally went the way you are headed.
Low voltage DC doesn't like long runs of wire, I parked the batteries & inverter right under the panels, including parking panels on the building the inverter/batteries are in.
That reduced losses a LOT, then drove AC to the buildings I occupied.

Something you might use,
Watts ÷ Volts = Amps
Watts ÷ Amps = Volts
Amps x Volts = Watts
Volts x Amps = Watts


----------

