"Dan Krueger" wrote in message
ink.net...
CalifBill wrote:

"Jack Goff" wrote in message
...

On Sat, 08 Apr 2006 00:54:50 GMT, Dan Krueger
wrote:


John Wentworth wrote:

"Mys Terry" wrote in message
om...


The distance in this case is a pretty important factor. I don't think
a 15 amp "tool" is going to be very happy on a 100 foot 12 gauge cord.



You're correct. To have a not greater than 3% voltage drop, a 15 amp
load
on a 100 foot cable would require #8 wire.
See http://www.elec-toolbox.com/calculators/voltdrop.htm for a voltage
drop
calculator.



Contractors use 100' 12ga extension cords every day to power large saws,
rotary hammer drills, and other big tools powered by their generators.
10ga or bigger would be expensive, hard to find, and not necessary.

Dan

Exactly correct. The calculator referenced only allows a 3% voltage
drop, which is only 3.6V for a nominal 120V ac circuit. Maybe if
you're running sensitive medical equipment that's necessary, but not
for power tools. A 15 amp circular hand saw is perfectly "happy"
running on 105V or so, over a 10% drop.

Think of it this way... your home wiring is usually 14ga for normal 15
amp branch circuits. Not unusual to have a 100ft run between the
breaker box and the outlets. Some voltage drop is expected, and
safety factors are built into everything you buy.

Jack



15 amp circuits are 14 gauge, and few run 100' inside a house. More like
50' at most. Contractors use 12 gauge because you can move the cord.
And most saws and tools are built to run in a 15 amp circuit, not draw 15
amps. Most are in the 7-8 amp range.

I think you are mistaken. 12 ga cords are heavier than 14 ga. Also,
anything with an electric motor will draw more power when you start it and
have it under a load than when it's running without a load. I have never
seen a standard 7-1/4" circular that would start and cut while drawing
only 8 amps. Most are rate at 12+ amps.

Dan

I say a 12 ga, which is normally a 20 amp circuit, because anything larger
is a real pain to move. Most saws will draw a lot less than 15 amps. My
Sil Mag 77 is rated 13 amps, and that is probably with the blade jammed or
near jammed.

"Don White" wrote in message
...
CalifBill wrote:


15 amp circuits are 14 gauge, and few run 100' inside a house. More like
50' at most. Contractors use 12 gauge because you can move the cord.
And most saws and tools are built to run in a 15 amp circuit, not draw 15
amps. Most are in the 7-8 amp range.

Maybe your rinky-dink Black & Decker stuff is 7 amps....
My Makita circular saw is 13 amps...
my Craftsman electric chain saw is 12 amps
my Toro Electric snowthrower is 12 amps...
etc...

That is with the blade almost locked or starting for a very short time. I
run a Skil Mag 77 worm drive and it is rated 13 amps. If they drew 15 amps
the circuit breaker would always be tripping.

"Wayne.B" wrote in message
...
On Sat, 08 Apr 2006 00:54:50 GMT, Dan Krueger
wrote:

Contractors use 100' 12ga extension cords every day to power large saws,
rotary hammer drills, and other big tools powered by their generators.
10ga or bigger would be expensive, hard to find, and not necessary.

I built my own 10ga extension once upon a time for doing boatyard work
at a distance from outlets. I bought a 250 ft roll of 10/3 from a
distributor at a half decent price, put my own connectors on it, and
stored the whole thing on an inexpensive garden hose reel.

Worked great, cost less than $100, everthing included.


When we had the house in Florida I had a concrete slab poured to park a
motorhome on. It was about 300 feet from the house power panel and I ran a
30 amp, 120 volt underground service to it. With consideration to voltage
drop, I used number eight wire for the hot and neutral and number 10 for the
ground. Even with that, I often would measure 105 volts at the RV,
particularly when the overall Florida Light and Power grid drooped during
high load periods.

Speaking of Florida .... today's April 9th and we had a mixture of rain,
freezing rain, sleet and snow all day today up here. I now remember why we
waited until late May to return to MA when we wintered down there.

RCE

On Sun, 09 Apr 2006 03:47:35 GMT, "Calif Bill"
wrote:


"Don White" wrote in message
...
CalifBill wrote:


15 amp circuits are 14 gauge, and few run 100' inside a house. More like
50' at most. Contractors use 12 gauge because you can move the cord.
And most saws and tools are built to run in a 15 amp circuit, not draw 15
amps. Most are in the 7-8 amp range.

Maybe your rinky-dink Black & Decker stuff is 7 amps....
My Makita circular saw is 13 amps...
my Craftsman electric chain saw is 12 amps
my Toro Electric snowthrower is 12 amps...
etc...

That is with the blade almost locked or starting for a very short time. I
run a Skil Mag 77 worm drive and it is rated 13 amps. If they drew 15 amps
the circuit breaker would always be tripping.

Remember that a 15 amp circuit breaker can carry far more than 15 amps
for a period of time. Circuit breaker have "trip curves", and a
typical 15 amp breaker can carry 15 amps for over 15 MINUTES before
tripping. At 30 amps it takes 7 seconds to trip, and at 60 amps it
still takes 1 second.

A 15 amp saw, dynamically drawing 15+ amps, would pose no problem for
a 15 amp breaker.

Jack

"Jack Goff" wrote in message
...
On Sun, 09 Apr 2006 03:47:35 GMT, "Calif Bill"
wrote:


"Don White" wrote in message
...
CalifBill wrote:


15 amp circuits are 14 gauge, and few run 100' inside a house. More
like
50' at most. Contractors use 12 gauge because you can move the cord.
And most saws and tools are built to run in a 15 amp circuit, not draw
15
amps. Most are in the 7-8 amp range.

Maybe your rinky-dink Black & Decker stuff is 7 amps....
My Makita circular saw is 13 amps...
my Craftsman electric chain saw is 12 amps
my Toro Electric snowthrower is 12 amps...
etc...

That is with the blade almost locked or starting for a very short time. I
run a Skil Mag 77 worm drive and it is rated 13 amps. If they drew 15
amps
the circuit breaker would always be tripping.

Remember that a 15 amp circuit breaker can carry far more than 15 amps
for a period of time. Circuit breaker have "trip curves", and a
typical 15 amp breaker can carry 15 amps for over 15 MINUTES before
tripping. At 30 amps it takes 7 seconds to trip, and at 60 amps it
still takes 1 second.

A 15 amp saw, dynamically drawing 15+ amps, would pose no problem for
a 15 amp breaker.

Jack

Depends on the breaker as to how fast it trips. There are different
"curves" for breakers. I think most home ones are Curve "C".

On Sun, 09 Apr 2006 21:03:21 GMT, "Calif Bill"
wrote:


"Jack Goff" wrote in message
.. .
On Sun, 09 Apr 2006 03:47:35 GMT, "Calif Bill"
wrote:


"Don White" wrote in message
...
CalifBill wrote:


15 amp circuits are 14 gauge, and few run 100' inside a house. More
like
50' at most. Contractors use 12 gauge because you can move the cord.
And most saws and tools are built to run in a 15 amp circuit, not draw
15
amps. Most are in the 7-8 amp range.

Maybe your rinky-dink Black & Decker stuff is 7 amps....
My Makita circular saw is 13 amps...
my Craftsman electric chain saw is 12 amps
my Toro Electric snowthrower is 12 amps...
etc...

That is with the blade almost locked or starting for a very short time. I
run a Skil Mag 77 worm drive and it is rated 13 amps. If they drew 15
amps
the circuit breaker would always be tripping.

Remember that a 15 amp circuit breaker can carry far more than 15 amps
for a period of time. Circuit breaker have "trip curves", and a
typical 15 amp breaker can carry 15 amps for over 15 MINUTES before
tripping. At 30 amps it takes 7 seconds to trip, and at 60 amps it
still takes 1 second.

A 15 amp saw, dynamically drawing 15+ amps, would pose no problem for
a 15 amp breaker.

Jack

Depends on the breaker as to how fast it trips. There are different
"curves" for breakers. I think most home ones are Curve "C".


Of course. The one I quoted was for a Square D "QO" breaker, a
common, high-quality home panel breaker. They don't identify the
curve by a C designation, but rather by a number. The curve PDF is on
their website.

Jack

Wayne.B wrote:

On Sat, 08 Apr 2006 00:54:50 GMT, Dan Krueger
wrote:


Contractors use 100' 12ga extension cords every day to power large saws,
rotary hammer drills, and other big tools powered by their generators.
10ga or bigger would be expensive, hard to find, and not necessary.


I built my own 10ga extension once upon a time for doing boatyard work
at a distance from outlets. I bought a 250 ft roll of 10/3 from a
distributor at a half decent price, put my own connectors on it, and
stored the whole thing on an inexpensive garden hose reel.

Worked great, cost less than $100, everthing included.


There's nothing wrong with that provided it's not a job site OSHA might
visit. The hardest part of making an extension cord like that would be
finding 10ga male and female ends. If they are rated for 12ga then the
250' of wire between the two might as well be 12ga.

Dan

On Mon, 10 Apr 2006 22:52:56 GMT, Dan Krueger
wrote:

Wayne.B wrote:

On Sat, 08 Apr 2006 00:54:50 GMT, Dan Krueger
wrote:


Contractors use 100' 12ga extension cords every day to power large saws,
rotary hammer drills, and other big tools powered by their generators.
10ga or bigger would be expensive, hard to find, and not necessary.


I built my own 10ga extension once upon a time for doing boatyard work
at a distance from outlets. I bought a 250 ft roll of 10/3 from a
distributor at a half decent price, put my own connectors on it, and
stored the whole thing on an inexpensive garden hose reel.

Worked great, cost less than $100, everthing included.


There's nothing wrong with that provided it's not a job site OSHA might
visit. The hardest part of making an extension cord like that would be
finding 10ga male and female ends. If they are rated for 12ga then the
250' of wire between the two might as well be 12ga.

Dan

Actually, that's not true. If what you are trying to accomplish is
less voltage drop under load, having the larger wire is exactly the
ticket. The drop is along the entire length of wire, and going to a
larger gauge means less resistance per foot, so less drop.

Now if you were to exceed the current-carrying capacity of the ends,
that's a different story. But that is not what was under discussion
here.

Besides, why would OSHA care? Unless they have a rule concerning an
extension cord's length, they aren't going to care if you're using an
extension cord that's over-engineered for it's use. Now if you tried
to do that same thing with lamp zip-cord, they'd nail you!

Jack

There's nothing wrong with that provided it's not a job site OSHA might
visit. The hardest part of making an extension cord like that would be
finding 10ga male and female ends. If they are rated for 12ga then the
250' of wire between the two might as well be 12ga.

Dan


I disagree. What he would be doing is effectively reducing the resistance of
the 250' length of the circuit. Since he's only running a 20A circuit, the
connectors wouldn't factor in as long as they are rated for 20A. His idea of
using larger guage wire would result in less voltage loss, and higher
capacity. Much less likely to overload and catch fire, especially if the
wire gets damaged in any way (as often happens on a construction site). Also
much better for electric motors. Very good idea for a 250' circuit.

You could do the same thing with a garden hose- using same size male and
female couplers on the ends as smaller hose, but increasing the diameter of
the hose will result in higher water pressure over a given distance.

On Mon, 10 Apr 2006 22:52:56 GMT, Dan Krueger
wrote:

If they are rated for 12ga then the
250' of wire between the two might as well be 12ga.

Not really. Remember that the only reason for using 10ga is to
minimize IR losses on a 250 ft run. Standard 12ga ends work just
fine.