I guess, if you don't want to just throw the circuit breaker. You can if
you want to, just make sure that the switch being used disconnects BOTH hot
leads and not just one and that it can handle the current load of the
circuit as well.
In this application the breaker will not be switching any current so its
life should not be impacted. Also, breakers of 30 amps and less don't
seem to be impacted when used to interrupt current. Switching larger
breakers when carrying large currents can impact their life in my
My personal preference when working on tools that need to be turned off
for service is to place the plug on the tool where I can see it before
and while my hand is at risk. Maybe I'm paranoid but unplugging it is
far more certain than remembering to turn a switch or breaker off.
Roy Smith wrote:
I don't believe it's the current interruption that causes the wear, it's
just the mechanical movement of the internal parts. Circuit breakers
(unlike normal switches) are designed to interrupt currents many (like
100's) times their rated capacity. They're also designed to trip even
if the external handle is mechanically held in the "ON" position. The
design tradeoffs required to meet those requirements usually involve
some kind of spring-loaded mechanism, which leads to a relatively high
mechanical wear each time the machanism is cycled.
If the contactors can handle interrupting a 1000 A overload, the arcing
caused by interrupting a 20 A load isn't going to be significant.
There's no doubt that that's the safest way to do it.
This is probably a silly response, but when I'm sticking my hand where it
could easily be turned into ground hamburger or sliced ham, I think I'd have
a happier feeling about it seeing a cable unplugged vs. a switch that's up,
or was it down, or...you get the idea :)
Well, I think it is more a question of how do you know the device has no
juice? Some people prefer the unplug method because you can visually
There was a recent question here on having a lighted switch that had two
lights, one for when the switch was on and another of a different color
for when it was off (that way you don't accidentally fry/butcher yourself
if the light bulb for "on" went out). I have also seen in a book a tip
about tying a short piece of rope/cord between the blade change tool and
the plug from the machine. That way you cannot possibly use the tool
unless you first unplug the machine.
Anyway, it's all about personalities I think. For me the unlpug method
works, but other people might want another way to assure the power's off.
All of our 220v tools are just wired directly to the circuit with wire
nuts, no plugs/outlets anywhere. Wasnt my decision, doesnt make me
particularly happy. Meant that when the switch on the drum sander melted
a spade lug, I had to go find the stupid breaker just to safely open it >:O
On Wed, 04 Feb 2004 21:08:09 +0000, gabriel wrote:
You can; just make sure it is a double pole switch rated for the amperage
I put one on my DC to avoid having to get back there.
Like all the other replies you got, I like to unplug my TS. You can't be
(breakers should not be used as switches unless they are designed for that
application, which is unlikely.)
When I change a blade, I _really_ want to see that cable and plug laying on
the top of the tool. Then I know for sure it is safe to work on the blade.
Have your electrician place the new 230 outlet where it is real easy to get
I had my planer hardwired to an approved disconnect switch for a while. I
Never got over the uneasiness when working on the knives and not seeing
where the end of the cord was. Take the recommendation of putting the outlet
in a convenient location and pull the plug.
Every 220 in my shop is not a 'plug' in the wall. Instead they are all
a short length (14" or so) of flexible 12-3 coming out of the box on
the wall. Makes unplugging easy.
It's near impossible for me to reset my planer knives without
accidentally hitting the on-switch with my knee. It's just in a bad
place so when I set the knife on top, kneel down to test it with the
dial gauge, then get up off my knees, my left knee always hits the
switch. I've never turned it on but I sure feel better knowing there
is no juice present.
If MY hands were in jeopardy, I'd open the breaker to the 220 leg feeding
the outlets. If you current configuration doesn't allow that I believe I
change it. Hands are a rather critical appendage! Keeping power off the
machines when repairing or adjusting is only common sense to me.
This is not a good idea. Instead have the 220v outlet on the wall, and then
screw another 220v outlet onto the side of your tablesaw. The outlet on
your TS has a 220V plug coming out of it to plug into the wall. Then plug
your TS into the outlet on the side of your TS.
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