Wire size and type?

[CentralFL]

So we finished the barn and now it needs 50 amp service. We plan to sub off the garage (200 amp panel). My issue is in wire type selection, based on the online calculators the 450 ft run need 2/0 aluminum triplex UDR (Direct Burial) to support 50 amp 240. Pricing is 900+- per 500' roll locally.

Is it any cheaper to run a different type of wire in conduit, and is 2/0 going to be suitable? I am in Florida and the wire will be buried along an area where mechanical damage is unlikely. Thanks!

 

[pattenp]

You need to use 4 conductors, not 3. You can use Quadruplex URD but it needs to be terminated outside of the building because code does not allow it to be run inside. It does not have fire resistant insulation.

 

[Charles (in GA)]

Need quadplex if you are running 240v.

 

[CentralFL]

You need to use 4 conductors, not 3. You can use Quadruplex URD but it needs to be terminated outside of the building because code does not allow it to be run inside. It does not have fire resistant insulation.

What is the correct way to terminate outside the building without using a meter can(and the outside lugs)? Thanks

 

[pattenp]

You can transition to different wire for the run to the inside of the building using a large junction box. You can use Polaris connectors or splice/reducers for the splice connections.

If you find MHF (Mobile Home Feeder) in 2/0-2/0-2/0-1 then that may be your best option. The MHF can run from panel to panel and only needs to be in conduit where above ground and inside the building.

Here it is at HomeDepot... http://www.homedepot.com/p/Southwir...Cable-28713601/202316460?N=5yc1vZbm7vZ1z0zudg

*

 

[toplessHO]

whos your power company and where are you located(city)?

 

[CentralFL]

Myakka City, FL , Peace River Electric.

Thanks!

 

[Charles (in GA)]

The Southwire calculator shows that if you are willing to accept a 5% voltage drop (it actually calculates 4.4%) and will drop down to 40 amps, that #2 AL will work, thus the 2-2-2-4 MHF would work.

At 45 amps, it shows a 4.96% drop on #2 AL, Problem is, some manufacturers, such as Siemens do make 45 amp double pole breakers, however, while a common 50 amp QP series breaker is about $14, the 45 amp QP series breaker is..... get this..... are you sitting down? $103!!!!!!!!!!1

Charles

 

[theoldwizard1]

The Southwire calculator shows that if you are willing to accept a 5% voltage drop (it actually calculates 4.4%) and will drop down to 40 amps, that #2 AL will work, thus the 2-2-2-4 MHF would work.

At 45 amps, it shows a 4.96% drop on #2 AL, Problem is, some manufacturers, such as Siemens do make 45 amp double pole breakers, however, while a common 50 amp QP series breaker is about $14, the 45 amp QP series breaker is..... get this..... are you sitting down? $103!!!!!!!!!!1

Charles

MHF is the best bang for the buck ! MHF CAN be run above ground or inside of a building if it is in conduit.

Square D QO 40A or 45A breakers are cost between $30-$50.

 

[CentralFL]

So with voltage drop... Is a 1 ton reverse cycle going to be happy running or burn out quicker than usual? I appreciate all the information. MHF can be run in a conduit underground?

 

[toplessHO]

check with your power company and see if they can supply the wire.

 

[CentralFL]

I did, they refuse to recommend anyone and if they run it, it is over 3K.

 

[CentralFL]

Where is the best place to buy wire? Online?

 

[Charles (in GA)]

Lowes or Home Depot for the wire. You need to find out what the current requirements for the heat pump you are considering. Need to talk to some HVAC techs.

HD for example shows homeline 40 amp DP breaker at $8.25 and QO breaker at $15.44. Oddly, the QO DP breaker from HD in 45 amp is $13.65 and the Homeline is $8.29.

Anyhow, they are available, just gotta look for them.

 

[ishiboo]

How large is this barn and what will be the uses? 45A seems pretty tight if you will ever have an air compressor or welder/plasma/etc. 500' of 2/0-2/0-2/0-1 MHF is $1400, 2-2-2-4 is $700. I would carefully consider whether or not this is worthwhile unless you only are using the building for storage.

Not saying many people can't get by with 45A, just saying now is the time to think about it!

 

[theoldwizard1]

So with voltage drop... Is a 1 ton reverse cycle going to be happy running or burn out quicker than usual?

Most modern heat pumps or A/C units are design for wide input voltage (tyicall something like 200-250V). Check your owners manual. At a lower supply voltgae they will draw a bit more current. Even a 2 ton unit will be nowhere near a 40A draw.

Voltage drop is based on current draw being used. The number you saw before are at MAXIMUM current draw.

I appreciate all the information. MHF can be run in a conduit underground?

Yes, it can. Not a requirement.

If you are planning on running a welder, they go by "average" current, because the amount of time it is actually making and arc is relatively low compared the the amount of time it is in standby.

 

[Charles (in GA)]

How large is this barn and what will be the uses? 45A seems pretty tight if you will ever have an air compressor or welder/plasma/etc. 500' of 2/0-2/0-2/0-1 MHF is $1400, 2-2-2-4 is $700. I would carefully consider whether or not this is worthwhile unless you only are using the building for storage.

Not saying many people can't get by with 45A, just saying now is the time to think about it!

How true!!! The old saying "you get what you pay for" certainly applies here.

Home Depot web site is showing 2/0-2/0-2/0-1 MHF on a 1000 ft spool for $1227.

Even with 2/0 wire, a 5% drop allowed and 450 ft, the Southwire calculator shows a max of 80 amps, 4.89% drop.

The distance is a killer.

 

[theoldwizard1]

How large is this barn and what will be the uses? 45A seems pretty tight if you will ever have an air compressor or welder/plasma/etc.

Worst case is probably a plasma cutter because it requires air (compressor) in addition to the arc generator.

You would probably have to turn the A/C off while running the compressor and plasma.

 

[pattenp]

How true!!! The old saying "you get what you pay for" certainly applies here.

Home Depot web site is showing 2/0-2/0-2/0-1 MHF on a 1000 ft spool for $1227.

Even with 2/0 wire, a 5% drop allowed and 450 ft, the Southwire calculator shows a max of 80 amps, 4.89% drop.

The distance is a killer.

That's 500ft, not 1000ft. A 1000ft of 2/0 MHF for $1227 would be a great deal.