Generator-To-Dwelling: Electrical Cord Length/Diameter?

 

Can anybody venture some numbers vis-a-vis generator load and extension cord
length/diameter?

I'm guessing it's something that anybody who knows basic electrical stuff can
compute.

Max continuous load: 1.6kw (Honda EU2000)

Got a paint locker/storage shed that I could run the gennie inside of, but it
would need 125 or 150 feet of electrical line to get from the dwelling to the
generator - and some more to reach wherever in the dwelling power is needed.

I've got 50' of some pretty heavy stuff.   It says "10/3 SJTW E-25411  FT2" on
the covering.   Wondering if two more 50' runs would do the trick.

Seems to me that at some point a heavy enough cord is equivalent to the stuff
they use to wire the interior of a house - and they make some pretty long runs
with that.

--
PeteCresswell

 



That will do the job, but if you want to go 150 feet, there will be some
voltage drop. Buy 8/3 for the additional length, if you can afford it.

 

10/3  or 8/3 is one more wire than you need. The 3 means there are 3
conductors for 220V. I would use type UF wire which can be direct
buried with or without conduit. That is a great generator !

 

Per sparky:

Would I need 3-conductor for the ground?  Or is a ground irrelevant in this
situation for the run from generator to the box near the dwelling?

i.e. Run just two wires from the gennie to a box on a stake near the dwelling,
then a ground rod from the box into the soil - and 3 wires from the box to
whatever plugs into it.

I like the idea of a buried/dedicated line.    Makes firing the thing up and
shutting it down sound a lot quicker/easier than uncoiling the cable and then
rewinding it - especially in foul weather.
--
PeteCresswell

 

(PeteCresswell) wrote:

The formula for calculating the voltage drop over a resistance is
Voltage = Current X Resistance (V=IR or E=IR). Another formula is Power
= Amps x Volts (P=IV). Some additional Ohms Law formulas can be found
at:

http://www.the12volt.com/ohm/ohmslaw.asp

The resistance of various gauges of wire can be found at:

http://www.interfacebus.com/Reference_Cable_AWG_Sizes.html
or:
http://www.epanorama.net/documents/wiring/wire_resistance.html

In doing the calculation, you have to include the return current. In
otherwords, double the length of the cord. So, for 150' of 10 AWG the
approximate voltage drop for 1600 Watts would be as follows:

P=IV
I = 1600W / 120V
I = 13.33 A

V = IR
V = 13.33A x 0.3054 ohms
V = 4.071 Volts

To that we might need to add a couple of volts of drop for the
connectors.

So, assuming that your generator outputs 120V, you would lose
approximately 4V over the cable and maybe 1 or 2 Volts for the
connectors. Plugs and sockets seem to "wear out" over time when
conducting large amounts of current. So, with every hundred hours of
use, for example, I would wrap my hand around the plug and socket (in
dry weather of course) and make sure they are not running hot.

The bottom line is that you would probably be getting about 115 volts
or so to the load which is more than adequate. Actually, if memory
serves, I think my EU2000 puts out about 122V, by the way.

The resistance of 12 AWG wire used in houses is 0.1619 ohms per 100
feet. The resistance of 10 AWG wire is 0.1018 ohms per 100 feet. So,
100 feet of 12 gauge in a house would produce the same voltage drop as
a 159.037 feet of 10 gauge.

That's all assuming that I did the calculations correctly, of course.