Help me solve a debate over electrical use.

[Eric DeSilva]

As stated above by others, if there is a switch, when in the "off" position, teh circuit is "open".

Not to single your post out--I've seen this in other posts in the thread--but I'm not sure I understand what distinction you are making. My TV has a switch--a pushbutton momentary contact switch--but that does not disconnect the TV from the mains electrically. It puts the TV into standby mode. Same with the "switch" on the front of my computer. A "switch" does whatever you wire it to do, which may or may not involve disconnecting the device entirely from the mains.

[David Epperson]

One of my friends -- who happens to be a perpetual worry-wart -- is so concerned about safety and electrical use, she unplugs everything when she closes up. I mean everything: the drill press, lights, chop saw, claiming that leaving them in the 110 outlet uses up electricity and presents a safety hazard. OK, I understand battery chargers, because they have a transformer, but all those other tools don't draw a microamp unless they're turned ON.

OK, I know that there are exceptional situations (shorts, etc) that could remotely be a factor, but it simply isn't worth the stress and bother to unplug and replug every day.

So, chime in and settle the debate.

She could always treat her shop like mine. I have a single industrial duty disconnect by the door - when I throw it, everything is "unplugged" and voltage free. And since it disconnects both legs of the incoming power, lightning has nowhere to push current to. It can light up the ground circuit (temporarily), but very little else.

[Keith Outten]

Your electrical service entrance does a great job of isolating your circuits from the grid but it won't protect you from a local lightening strike whether the main breaker is on or off. You can spend millions of dollars designing breakers to withstand a direct lightening strike and they will fail every time. Nothing protects you from a lightening strike.

I unplug my CNC Router and my Laser Engraver when we have an electrical storm in my area. If lightening hits the house across the street both machines will probably be safe but a direct hit dosen't need wires to move in any direction it wants to go, case in point there is no wire between the cloud and the ground
.

[Matt Mackinnon]

I unplug my CNC Router and my Laser Engraver when we have an electrical storm in my area. If lightening hits the house across the street both machines will probably be safe but a direct hit dosen't need wires to move in any direction it wants to go, case in point there is no wire between the cloud and the ground
.

Lightning is just a very large electrical source. And it does follow the standard rules of electricity. One of them is that it will follow the path of least resistance. If you have a mechanical disconnect switch with a proper ground installed, then the ground is the path of least resistance, and it would follow that over bridging between open air to complete a circuit.

You are correct in saying there is no wire between the cloud and the ground, but if there was one there, then the lightning would run along that wire and you could predict where it would hit every time. That is why tall buildings put in lightning rods, to give a path of least resistance for lighting to travel rather than though the building.

But I do disconnect my Oneway lathe when I am not using it. To expensive to repair.

[Jacob Nothstine]

I unplug everything have a 4 and 6 year old who like to push buttons.

[ray hampton]

my battery charger got a stick-up that plainly advise all users to unplug the electrical cord before you unhook the battery cable and the same thing also apply to the cell phone chargers that plug into a wall outlet, the charger gets unplug first then the cell phone,I bought a tool similar to a Dremel but different name that I would turn it off then unplug the transformer and if I would turn the the tool back on , the transformer would store enough electric to run the tool

[Matt Marsh]

Lightning is just a very large electrical source. And it does follow the standard rules of electricity. One of them is that it will follow the path of least resistance. If you have a mechanical disconnect switch with a proper ground installed, then the ground is the path of least resistance, and it would follow that over bridging between open air to complete a circuit.

You are correct in saying there is no wire between the cloud and the ground, but if there was one there, then the lightning would run along that wire and you could predict where it would hit every time. That is why tall buildings put in lightning rods, to give a path of least resistance for lighting to travel rather than though the building.

But I do disconnect my Oneway lathe when I am not using it. To expensive to repair.

True to a point Matt, but the old yarn that electricity takes the path of least resistance can get you into trouble. The truth is, electricity takes ALL paths available, and the number of available paths increases as the voltage increases. It is nearly impossible to predict the amount of damage that a direct hit by lightning will cause, there are just way too many variables, and the voltage potential is awesome. The miniscule air gap that a set of switch contacts maintains is nothing to a direct hit. To top it all off, the most common type of grounding electrode(s) used in these shops is probably a rod type. These things are the least effective electrode available, even when properly installed. If your properly grounded disconnect switch is tied to a marginally effective grounding electrode system such as these, the switch contacts may still be the path of least resistance. I have personally rewired several lightning damaged houses and branch circuits. It is just crazy the unexpected things that happen!

[Lee Schierer]

my battery charger got a stick-up that plainly advise all users to unplug the electrical cord before you unhook the battery cable and the same thing also apply to the cell phone chargers that plug into a wall outlet, the charger gets unplug first then the cell phone,I bought a tool similar to a Dremel but different name that I would turn it off then unplug the transformer and if I would turn the the tool back on , the transformer would store enough electric to run the tool

Your battery charger has a warning because disconnecting the cables from a battery while energized can create a spark and potentially ignite the hydrogen generated by the charging process. Cell phones and others don't generate hydrogen so there is no need to unplug their chargers before disconnecting the device. As for transformers storing energy, unless your transformer has some really big power smoothing capacitors, there is no stored energy and certainly not enough to power a tool. Dremels had some really cheap on/off switches theat were easily turned on while handing the tool to change bits. When changing bits or blades in any tool it is highly advisable to unplug the tool.

[Ralph Lindberg]

Russell, I can honestly see the point. Electrical codes vary from one country to another, some require that each outlet be switched, to the outlet can be turned off.

The "entertainment" center is certainly the worst power suck (when "off"), since none of it is actually off. The DVR, TV, VCR, etc, anything with a remote is never truly "off"

See you tonight

[ray hampton]

Your battery charger has a warning because disconnecting the cables from a battery while energized can create a spark and potentially ignite the hydrogen generated by the charging process. Cell phones and others don't generate hydrogen so there is no need to unplug their chargers before disconnecting the device. As for transformers storing energy, unless your transformer has some really big power smoothing capacitors, there is no stored energy and certainly not enough to power a tool. Dremels had some really cheap on/off switches theat were easily turned on while handing the tool to change bits. When changing bits or blades in any tool it is highly advisable to unplug the tool.

transformers work because of the magnetic flux that cut thru. the copper wires and this will depend on the steel that the core are make from but some transformers core can stored magnetic flux for a period of time and this flux will allow the transformer to provide power after the tool were unplug but if you blink your eyes , you will miss it

[Jim Neeley]

Let's start a safety discussion by saying we cannot be 100% safe, we can only reduce the probability of a problem. Even if we locked ourselves in our room and never left we could have a heart attack and die, shocked by our lights, be hit by a tornado or earthquake or fall upon a flood of epic proportions. That doesn't mean we can't and shouldn't be smart.

Also, each of us have our own safety tolerances and there are likely things that we each are more or less concerned about. We don't get lightning here but I suspect if my neighbor's house was hit with lightning and it fried all of his electrical stuff (or a friend's friend) it would become important to me. Perhaps more important than it warrants, perhaps not. All of that said, here's my $0.02... YMMV.

We've talked about idle current for things such as battery chargers. I route mine through a power strip that also powers a couple of convenience floods in my shop. When I leave I turn off the lights and thereby the chargers. It's not a big deal or require extra effort but it is accomplished.

When my son was young I was very careful to unplug my saws and drop the plugs out of sight. Now that he is 22yo and in grad school I do not bother.

I have a friend with 6 young children who each had many friends who hung around and a shop. His risk is higher. I helped him to change out his receptacles to all locking plugs and then built short (~1') "jumper" cables with a locking plug on one end and a non-locking receptacle (that matches the plug on the tools) on the other. Once the receptacles were changed he only required 3 jumper cables (one for 120V 20A and two for 240V). He would take the three jumpers into the house and put them in his closet when he was done working ensuring none of his power saw / sanding / lathe/ etc. tools could be quickly energized by little hands. That seemed reasonable considering his risk and his concern.

That's my $0.02.. YMMV!

Jim in Alaska

[Dan Hintz]

transformers work because of the magnetic flux that cut thru. the copper wires and this will depend on the steel that the core are make from but some transformers core can stored magnetic flux for a period of time and this flux will allow the transformer to provide power after the tool were unplug but if you blink your eyes , you will miss it

Any residual power you see coming from a power supply after you unplug it is from the smoothing capacitors, not the transformer...

[Russell Neyman]

This discussion (which has been moved to another forum, despite being quite relevant an popular among the woodturners) has taken a turn toward an aspect of safety beyond fire, so I'll add a point.

One problem with leaving power tools unplugged is that it gives you a false sense of security about the ON/OFF status. I'll give you an example. My brother came to visit, and absent mindedly flicked the switch on, off, and on again. Since it was unplugged, no one realized that he left it in the on position, so when I plugged it scared the crap out of me, snagging a rag I placed over a bowl in the chuck and creating quite a racket. Yeah, I know we all should carefully check every single situation before doing anything in a wood shop, but that realistically doesn't happen.

[Art Mann]

I'm just glad I don't live my life in fear that all sorts of improbable catastrophes are going to happen. I would not spend a minutes each day plugging and unplugging my woodworking machinery any more than I would plug and unplug my entertainment equipment or kitchen appliances. That is why I buy insurance.

[Anthony Whitesell]

All electric machinery that has a ON/OFF switch draws 0 voltage in the off position (otherwise the machine would be running)! The ON/OFF switch physically cuts the electrical circuit so its the same as if it not pugged in at all (after the switch point, that is). Now places that are prone to lightning, surges and brown outs have their own concerns and there are some whole home (circuit breaker box versions) surge protectors that can assist with the strikes and surges but even they aren't 100% reliable. So for an energy saving option....it's nonsense..... for switches machines. Now if your a moron, like I have been, and left the radio, lights and fan running all night... well that doesn't save any energy! I forgot to go back out and shut off things after coming in for a drink and staying for supper!

That's what I don't like about the Grizzly G0490 jointer. There is no "ON/OFF" switch, only start and estop. When it is plugged in, it draws current (albeit not much). I unplug it because I don't like the control panel. The Grizzly bandsaw and the '52 Craftsman tablesaw (with Rockler paddle switch installed) stay plugged in, unless there a contractor working in the house (usually the heating guy) or if I'm going away for more than a few days.