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Toller
 
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Default Combining wires to avoid voltage drop? 12/4 cable?

I know it is unsafe to combine wires to avoid over loading a circuit; like
using two #14 to carry 18a. One could come loose and the other is
overloaded.
But how about doing it to avoid voltage drop?

I have no power at my dock, and carrying my generator down 130 stairs isn't
any fun. I have done it once, and probably never will again.
It is over 120ft, so a #12 extension cord would have excessive voltage drop
on a circular saw

A guy is selling a 250 roll of 12/4 wire for $50. As far as I can tell, it
is something for audio hookups and has no ground. Could I treat it as 12/3
with an insulated ground, connect two of the wires together to reduce
voltage drop, and leave it as a permanent extension cord? I figure that
with two wires connected, the VD would be reduced to a manageable level.
(yes, I realize the return is only single, but it seems okay if you average
the two) There is no reason the wires should ever come undone, but if they
did, the worst that could happen is burning out my saw.

Does this make sense?
Is this 12/4 stuff safe for 120v?

I did the same thing when I installed my transfer switch. All I needed was
12/2, but I used 10/3 in case someone needed it in the future; since the
labor was the same either way. I connected two wires together to reduce VD.
A little overkill, but it was just sitting there anyhow.


  #2   Report Post  
Pop
 
Posts: n/a
Default Combining wires to avoid voltage drop? 12/4 cable?

At best, you'll get something like an almost 50% cut in the
voltage drop, all things assumed to be equal which is never the
case; a real world figure would be in the 40-45% range at a
nominal current, and possibly much less at higher currents.

So, uhh, why not do it right, use the correct derating factors
for that length run, and work accordingly. Most any wire has the
specs you need to be sure you won't hit the brownout margin for
your saw. Use 106Vac min and = 120Vac nominal for your calcs
and you'll be fine, and using resistive calcs (E=IR) will put you
in the ballpark for this; don't sweat the small stuff of
inductance and all that for this kind of calcs.
I don't subscribe to the "fix it later if it's a problem" when
it can be done right the first time and not have to be bothered
with again.

HTH,


"Toller" wrote in message
...
:I know it is unsafe to combine wires to avoid over loading a
circuit; like
: using two #14 to carry 18a. One could come loose and the other
is
: overloaded.
: But how about doing it to avoid voltage drop?
:
: I have no power at my dock, and carrying my generator down 130
stairs isn't
: any fun. I have done it once, and probably never will again.
: It is over 120ft, so a #12 extension cord would have excessive
voltage drop
: on a circular saw
:
: A guy is selling a 250 roll of 12/4 wire for $50. As far as I
can tell, it
: is something for audio hookups and has no ground. Could I
treat it as 12/3
: with an insulated ground, connect two of the wires together to
reduce
: voltage drop, and leave it as a permanent extension cord? I
figure that
: with two wires connected, the VD would be reduced to a
manageable level.
: (yes, I realize the return is only single, but it seems okay if
you average
: the two) There is no reason the wires should ever come undone,
but if they
: did, the worst that could happen is burning out my saw.
:
: Does this make sense?
: Is this 12/4 stuff safe for 120v?
:
: I did the same thing when I installed my transfer switch. All
I needed was
: 12/2, but I used 10/3 in case someone needed it in the future;
since the
: labor was the same either way. I connected two wires together
to reduce VD.
: A little overkill, but it was just sitting there anyhow.
:
:


  #3   Report Post  
FDR
 
Posts: n/a
Default Combining wires to avoid voltage drop? 12/4 cable?


"Toller" wrote in message
...
I know it is unsafe to combine wires to avoid over loading a circuit; like
using two #14 to carry 18a. One could come loose and the other is
overloaded.
But how about doing it to avoid voltage drop?

I have no power at my dock, and carrying my generator down 130 stairs
isn't any fun. I have done it once, and probably never will again.
It is over 120ft, so a #12 extension cord would have excessive voltage
drop on a circular saw

A guy is selling a 250 roll of 12/4 wire for $50. As far as I can tell,
it is something for audio hookups and has no ground. Could I treat it as
12/3 with an insulated ground, connect two of the wires together to reduce
voltage drop, and leave it as a permanent extension cord? I figure that
with two wires connected, the VD would be reduced to a manageable level.
(yes, I realize the return is only single, but it seems okay if you
average the two) There is no reason the wires should ever come undone, but
if they did, the worst that could happen is burning out my saw.

Does this make sense?
Is this 12/4 stuff safe for 120v?


Unless it's clearly marked for high voltage use, I would not use it.


I did the same thing when I installed my transfer switch. All I needed
was 12/2, but I used 10/3 in case someone needed it in the future; since
the labor was the same either way. I connected two wires together to
reduce VD. A little overkill, but it was just sitting there anyhow.



  #4   Report Post  
 
Posts: n/a
Default Combining wires to avoid voltage drop? 12/4 cable?

Especially in a marine environment, I'd suggest that you focus on doing
it right (including safely) rather than on saving a few $. Not meaning
to be cute, but one ER trip or casket purchase can really tip the
accounting against you.

One possible alternative is a battery-powered saw. True, less powerful
than 120v, and more expensive, but much less likely to zap you when
wet. With gen at the head of the pier, you could take the batteries
there for charging.

HTH,
J

  #5   Report Post  
Toller
 
Posts: n/a
Default Combining wires to avoid voltage drop? 12/4 cable?

Is this 12/4 stuff safe for 120v?


It's not safe for use outdoors, where exposure to moisture and UV are
factors.

That's a good point. It claims to be UV stable, but says nothing about
moisture.
Oh well. Thanks to all.




  #6   Report Post  
Andy Hill
 
Posts: n/a
Default Combining wires to avoid voltage drop? 12/4 cable?

"Toller" wrote:
I know it is unsafe to combine wires to avoid over loading a circuit; like
using two #14 to carry 18a. One could come loose and the other is
overloaded.
But how about doing it to avoid voltage drop?

I have no power at my dock, and carrying my generator down 130 stairs isn't
any fun. I have done it once, and probably never will again.
It is over 120ft, so a #12 extension cord would have excessive voltage drop
on a circular saw

A guy is selling a 250 roll of 12/4 wire for $50. As far as I can tell, it
is something for audio hookups and has no ground. Could I treat it as 12/3
with an insulated ground, connect two of the wires together to reduce
voltage drop, and leave it as a permanent extension cord? I figure that
with two wires connected, the VD would be reduced to a manageable level.
(yes, I realize the return is only single, but it seems okay if you average
the two) There is no reason the wires should ever come undone, but if they
did, the worst that could happen is burning out my saw.

Does this make sense?
Is this 12/4 stuff safe for 120v?

I did the same thing when I installed my transfer switch. All I needed was
12/2, but I used 10/3 in case someone needed it in the future; since the
labor was the same either way. I connected two wires together to reduce VD.
A little overkill, but it was just sitting there anyhow.

As for the voltage drop Q, sure, you can do it although it's more than a bit
sloppy (the first sign of problem would probably be either the cord or saw
frying, depending on the currents involved).

As to the specifics of using audio wire for this application, that sounds like
bad mojo. Insulation most likely not rated for the voltage, nor the moisture,
nor the UV exposure.
  #7   Report Post  
SQLit
 
Posts: n/a
Default Combining wires to avoid voltage drop? 12/4 cable?


"Toller" wrote in message
...
I know it is unsafe to combine wires to avoid over loading a circuit; like
using two #14 to carry 18a. One could come loose and the other is
overloaded.
But how about doing it to avoid voltage drop?

I have no power at my dock, and carrying my generator down 130 stairs

isn't
any fun. I have done it once, and probably never will again.
It is over 120ft, so a #12 extension cord would have excessive voltage

drop
on a circular saw

A guy is selling a 250 roll of 12/4 wire for $50. As far as I can tell,

it
is something for audio hookups and has no ground. Could I treat it as

12/3
with an insulated ground, connect two of the wires together to reduce
voltage drop, and leave it as a permanent extension cord? I figure that
with two wires connected, the VD would be reduced to a manageable level.
(yes, I realize the return is only single, but it seems okay if you

average
the two) There is no reason the wires should ever come undone, but if they
did, the worst that could happen is burning out my saw.

Does this make sense?
Is this 12/4 stuff safe for 120v?

I did the same thing when I installed my transfer switch. All I needed

was
12/2, but I used 10/3 in case someone needed it in the future; since the
labor was the same either way. I connected two wires together to reduce

VD.
A little overkill, but it was just sitting there anyhow.


the NEC is pretty specific about paralleling conductors. You need to have at
least 1/0 awg before paralleling.

http://www.electrician.com/vd_calculator.html

Is this 12/4 audio cord even insulated for 300v? Lowest rating of most
extension cords.


  #8   Report Post  
Stormin Mormon
 
Posts: n/a
Default Combining wires to avoid voltage drop? 12/4 cable?

Might want to check Home Depot on their price for 250 feet of 10-2 WG. Might
be close to same price. Sounds like false economy. If it's exposed to
sunlight, go with UF.

--

Christopher A. Young
Do good work.
It's longer in the short run
but shorter in the long run.
..
..


"Toller" wrote in message
...
I know it is unsafe to combine wires to avoid over loading a circuit; like
using two #14 to carry 18a. One could come loose and the other is
overloaded.
But how about doing it to avoid voltage drop?

I have no power at my dock, and carrying my generator down 130 stairs isn't
any fun. I have done it once, and probably never will again.
It is over 120ft, so a #12 extension cord would have excessive voltage drop
on a circular saw

A guy is selling a 250 roll of 12/4 wire for $50. As far as I can tell, it
is something for audio hookups and has no ground. Could I treat it as 12/3
with an insulated ground, connect two of the wires together to reduce
voltage drop, and leave it as a permanent extension cord? I figure that
with two wires connected, the VD would be reduced to a manageable level.
(yes, I realize the return is only single, but it seems okay if you average
the two) There is no reason the wires should ever come undone, but if they
did, the worst that could happen is burning out my saw.

Does this make sense?
Is this 12/4 stuff safe for 120v?

I did the same thing when I installed my transfer switch. All I needed was
12/2, but I used 10/3 in case someone needed it in the future; since the
labor was the same either way. I connected two wires together to reduce VD.
A little overkill, but it was just sitting there anyhow.



  #9   Report Post  
Stormin Mormon
 
Posts: n/a
Default Combining wires to avoid voltage drop? 12/4 cable?

Oh, that's right. I missed that. The 12-4 is probably not UF.

--

Christopher A. Young
Do good work.
It's longer in the short run
but shorter in the long run.
..
..


"Captain Joe Redcloud©" wrote in message
A guy is selling a 250 roll of 12/4 wire for $50. As far as I can tell, it
is something for audio hookups and has no ground. Could I treat it as 12/3


It's not safe for use outdoors, where exposure to moisture and UV are
factors.


Captain Joe Redcloud©


  #10   Report Post  
Chris Lewis
 
Posts: n/a
Default Combining wires to avoid voltage drop? 12/4 cable?

According to Toller :
I have no power at my dock, and carrying my generator down 130 stairs isn't
any fun. I have done it once, and probably never will again.
It is over 120ft, so a #12 extension cord would have excessive voltage drop
on a circular saw

A guy is selling a 250 roll of 12/4 wire for $50.


As mentioned, this isn't rated for 120V, and probably won't stand up
to weathering/exterior use either. It'd become lethal within
a year of exposure (if not immediately).

If it's solid conductor, even worse.

Price out 10/2 (with ground) SO (preferably SOW) (stranded/flexible
heavy duty exterior extension cord), and compare with a "contractor's
extension cord" (_fat_ brightly coloured extension cords) in #10.
[These are SOW, but preassembled with plugs/sockets, and are often
somewhat cheaper than "off the roll" wire.]

Chances are you could do it for roughly $75-100. Not cheap, but
the only thing that'll stand up to any extended period of
deployment.

That said:

Ignore the next two paragraphs if this is for more than one project ;-)

I have been known to run a 12A chainsaw on the end of almost 200' of
linked together extension cords (about half #12, rest #14). It
didn't work great, and bogged down quite easily. But, with a gentle
touch, I managed to do what I needed to without blowing anything
up or producing any smoke.

What I'm trying to say is that you _could_ use your circular saw
on the end of a #12 extension cord if you were careful to not
jam the thing (back off at the slightest sign of slowing down),
went very slow, and didn't make a career out of it.
Do most of your cutting _before_ you take the lumber to the dock...
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.


  #11   Report Post  
Andy Hill
 
Posts: n/a
Default Combining wires to avoid voltage drop? 12/4 cable?

"SQLit" wrote:
"Toller" wrote in message
...
I know it is unsafe to combine wires to avoid over loading a circuit; like
using two #14 to carry 18a. One could come loose and the other is
overloaded.
But how about doing it to avoid voltage drop?

I have no power at my dock, and carrying my generator down 130 stairs

isn't
any fun. I have done it once, and probably never will again.
It is over 120ft, so a #12 extension cord would have excessive voltage

drop
on a circular saw

A guy is selling a 250 roll of 12/4 wire for $50. As far as I can tell,

it
is something for audio hookups and has no ground. Could I treat it as

12/3
with an insulated ground, connect two of the wires together to reduce
voltage drop, and leave it as a permanent extension cord? I figure that
with two wires connected, the VD would be reduced to a manageable level.
(yes, I realize the return is only single, but it seems okay if you

average
the two) There is no reason the wires should ever come undone, but if they
did, the worst that could happen is burning out my saw.

Does this make sense?
Is this 12/4 stuff safe for 120v?

I did the same thing when I installed my transfer switch. All I needed

was
12/2, but I used 10/3 in case someone needed it in the future; since the
labor was the same either way. I connected two wires together to reduce

VD.
A little overkill, but it was just sitting there anyhow.


the NEC is pretty specific about paralleling conductors. You need to have at
least 1/0 awg before paralleling.

http://www.electrician.com/vd_calculator.html

Is this 12/4 audio cord even insulated for 300v? Lowest rating of most
extension cords.

Drifting a bit, but does the NEC even address temporary stuff like "extension
cords" (other than the requirement that extension cords are not to be used for
permanent wiring)? Seems like more of a UL or OSHA issue.
  #12   Report Post  
Chris Lewis
 
Posts: n/a
Default Combining wires to avoid voltage drop? 12/4 cable?

According to Andy Hill :

Drifting a bit, but does the NEC even address temporary stuff like "extension
cords" (other than the requirement that extension cords are not to be used for
permanent wiring)? Seems like more of a UL or OSHA issue.


Strictly speaking, this is a "c*&p, my circular saw caught fire" issue ;-)
NEC doesn't cover this sort of wiring per-se, and "officially" this is
a UL (or CSA or CE or...) issue. However, this isn't an anal safety
rule sort of thing, more of a "it _will_ bite you"/"laws of physics"
sort of thing.

[The NEC does have some stuff to say about temporary wiring. Ie:
temporary wiring in many cases _is_ covered by NEC, ie: "event"
temporary wiring.]
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.
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