The local newspaper, for the past week, has covered a story of an electrical power surge, apparently caused by a car vs. power pole accident, which has caused numerous residents to have damaged TVs, refrigerators, computers, etc, from fried circuits. Most people interviewed said even appliances plugged into a surge protector were ruined. Edison Co.’s response so far has been only that the sudden spike was so severe that even the standard surge protectors did no good. This story has me thinking: could stationary power woodworking tools be damaged in the same way, such as at night when the tool was shut off? Or when the tool was in use, under power?
The only two tools I am really wondering about are (1) my bandsaw, which has a powered switch (when plugged in, a circuit in the switch can be heard to click on); and (2) my lathe, which has an electronic Leeson Speedmaster variable speed control. Both are 220V, and I have always left them plugged in overnight.
Anything to worry about or protections to take? If my TV went up in smoke, I would consider it almost a blessing, but not my tools. Any advice on this is appreciated. Gary.
Replies
"Edison Co.'s response so far has been only that the sudden spike was so severe that even the standard surge protectors did no good."
Well, maybe a really cheap surge protector. A good surge protector should withstand just about anything that could possibly come over the line, short of a lightning strike.
I don't know about the bandsaw switch (it might just be a relay that you're hearing), but it would be a good idea to have the electronic speed control surge protected. However, I don't know if that's possible. Does it use a single power cord for both the motor and the electronics? If so, then you'd have a hard time finding a surge protector with sufficient capacity to do any good. The good news, though, is that it most likely already has pretty good internal surge protection.
-Steve
After years in the Communication industry I can tell you that no surge protector offers complete protection regardless of cost. A direct lighting strike fries all. Period.
If the surge is large enough it will bridge circuit interrupters (switches, etc.) but it is not common.
Your home insurance policy may protect you from complete financial loss when lightening or a surge strikes. If the option presents itself (related to insurance) always choose replacement over repair. Lightening and huge surges cause damage to solid state circuitry that may not be immediately detecable and will fail later after the insurance-paid-for repair has taken place.
Peter
Here's a weird one for ya. The lights flickered on-off-on-off at my stepdaughter's place yesterday. Last night she couldn't get her laptop to boot up. Turned out the battery backup/surge protector was fried. She asked a neighbor, who works for the power company, what the heck was going on. He said that there was a branch laying across the lines in some remote place (it's all remote around here) and they didn't want to send a line crew out, so they were trying to "blast it off" by sending big surges through the lines!!!
Is there a class-action suit in this somewhere? Sheesh!forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
That sounds very urban legend-ish to me. Even if you could do such a thing (which I don't think you could without damaging the lines), there would be a huge risk of starting a fire.
-Steve
"He said that there was a branch laying across the lines in some remote place (it's all remote around here) and they didn't want to send a line crew out, so they were trying to "blast it off" by sending big surges through the lines!!!"What, does a big surge of current cause a lump in the wire that courses along like a snake swallowing an egg? Might cause an explosion if there were a kink in the wires somewhere. :)
BruceT
Although I doubt the story of removing the branch with a jolt is true, I actually witnessed a 'jump' in wires once. My business partner decided to correct a blown tubular fuse with a piece of 18 gauge wire, all unbeknownst to me.
When he switched the main switch on there was a loud bang. At the time my office overlooked the power connection to the building and I saw a single wave travel across the street to the mains then branch from there. Just like in a cartoon or something. I figure the current surge (likely 1000 amps or so before the wire vaporized) created opposing magnetic fields which bounced the cables.
Very cool.
Unfortunately he didn't kill himself (I later learned he was a thief), but how he managed to escape unscathed is a mystery.
The motor on my delta 8 in jointer fried the other day. I took it to the local motor shop, and the capacitor was shredded/exploded - looked like a firecracker that had blown up. There was a burned spot on the windings that went straight across in a line. The guy at the motor shop said it looked like a power surge had arced across that spot. He said no way it was from overheating, because the rest of the windings looked pristine. He said must have been a massive power surge or lightning.
I used it the night before without problems; it wouldn't start first thing in the morning. No storms that night, and the other stuff in the shop was fine (a refrigerator, fan, lights, cyclone dust collector, air compressor were all plugged in, but no damage elsewhere.
The breaker box, breaker, romex cable to the recepticle, and 240 extension cord (I make my own using 10 ga wire, never longer than 20 feet) are all fine. Voltage at every point (box, receptacle, end of extension cord, motor switch) all read 226 volts without any drop along the circuit. Everything is grounded properly.
There was a fire in a building next door a week before, but they were on a seperate sevice, and I had used the jointer several times after the fire/before it fried without trouble.
I'm no electrician by any means, but the only thing I can figure is that there was a huge voltage spike that arced across the motor, but I can't see how it could have jumped the motor switch without butning it up also.
I'll post a picture of the capacitor and windings (if i can figure out how).
Capacitors are known to spontaneously explode for a variety of reasons. A lab where I used to work had a hole burnt into a ceiling tile after a power supply engineer switched on a prototype with the shield off.
Usually, its semiconductor components which get fried from a surge because they tend to have low breakdown voltages.
The exploded capacitor could well have been caused by the arc across the windings. But I doubt that the arc was caused by a power surge.
-Steve
The arcing damage on the windings may be old damage that didn't prevent the motor from running and you just didn't discover it until the motor was disassembled because of the failed capacitor. Another possibility is that the explosion from the blown capacitor reached the armature through a hole in the motor housing.John White
Nearly all of your woodworking tools are going to be isolated from power by a physical switch contact, and will not be at risk. It would take a huge voltage to jump the gap of the switch contacts, and by this time, you've probably lost the entire house.
Your variable frequency drive is a different story, because in most cases, the VFD remains connected to incoming power, and the VFD is what provides electrical control to the motor. Moreover, the VFD is an electronic component, and as such, is more susceptible to power problems.
Surges are a much greater danger to modern electronics, TV, stereo, even your refrigerator and microwave, than to the tools in your shop which are generally computer chip free. You can protect everything in your house with a whole house surge protector. I had one installed a few years ago for a couple of hundred dollars. It is something you would probably want an electrician to do.
I suppose the other option might be to have a master circuit breaker in your shop that you could turn off.
I lost the control board on my pellet stove to a surge, cost me $300 to circumvent the board and now I don't have anywhere near the niceties re: control that I once had.
If a car is known to have hit the pole and it took out the transformer, I would think that any collateral damage should be covered too, as long as it's possible to prove that the crash caused it. Re: surges- they do a lot of damage when the device is on, but not nearly as much when it's off. If the surge is great enough to arc across the contacts of a mechanical switch when it's open, be happy that whatever the switch controls wasn't on.
"I cut this piece four times and it's still too short."
Gary,
You probably don't need to worry about the typical shop tool with only a switch and motor. Any device that mechanically disconnects the hot wire is probably OK. Even while they're connected (running), the motor windings are sized close enough to the breakers/fuses that they are unlikely the first to burn out.
Shop tools that have variable speed controls hopefully disconnect power to the electronic module mechanically. I don't trust that though and keep my router unplugged. I also throw the main disconnect switch (with fuse) next to my subpanel in the shop when I'm away or there are large storms. Can't stop those pesky drunks that aim for hydro poles though.
Computers are an exception in that they ground the chassis with the ground wire and the switching supplies are vulnerable to surges that show up between ground and neutral (common mode). Surge suppressors are a large topic and they come in lots of sizes and types. Whole house suppressors might use gas tubes to shunt the surge to neutral. Could create problems by opening large potential between neutral and ground. Point of use suppressors are often poorly designed but a good one at least provides MOVs between each pair (three) of wires. These devices are designed to take the brunt of the surge and burn or partially burn in the process. This is sacrificial and, like a helmet, should be replaced after such an event. A really good one will trip a fuse/breaker and leave the circuit open. A UPS should have protection in it that should be replaceable. Long rant, but the point is adding protection is a complex topic and different for every type of load.
When I have tried talking to Ontario's Hydro One about power outages and surges, they informed me that I should protect my own equipment with UPSs. Not very helpful for the price we pay here for electricity. I wouldn't worry too much about most shop equipment though.
Andy
There is a chance that you stuff could get fried, but it should be covered under your home owners policy. You need to read the fine print though. Some carriers put low limits on tools specifically. I have nationwide and had such a limit ($1,000), I had a $10,000 rider adder for $20 a year just for my tools. In my years of working in the telecommunications fields and computers, I have seen a lot of surge protectors. General rule of thumb is the more amps you need to protect the faster you want it, and the more expensive it gets (real $$$). There are many different technologies the most common is a MOV type device. At a certain voltage (rating) it will dissipate the voltage to ground. The lower the voltage rating the better. Speed of clamp can vary based on technology as well. Needless to say some people will ask me for recommendations and I generally say you get what you pay for. I have a surge protector that was around a $100 bucks that protects the home theater due to its value. For the computer my unit is around 50 bucks but the value is much smaller. I do not have a surge protector on my tools individually, but I do keep the circuit open in the box. Now this is done via the breaker, so If I took a lightning hit, that would not help, but then the fire policy would come into play. I would suggest you control it by just throwing the breakers when not in use and have insurance. Now for your computers, if you have phone line i.e. dsl, dial-up, or cable, be very careful! Generally the grounds in the phones and cable is very good. When you take a hit (from my experiences) it generally came in via one of the two and passed through the system to ground tearing up anything in between. That's why I have a surge protector that supports coax,telco, and power to separate those. Your protector should also have a ground indicator light! Usually it will turn red if good ground is not detected. No ground no protection. Finally, make sure your protection device is UL listed with a UL listing for surge devices (UL1449). I once saw a powerstrip for sale in walmart once that had a picture of a computer on the box giving the impression that it was a surge protector, but I flipped it over and all it had was a 15a circuit breaker, which will trip, but after your device is fried. Basically protection is worth what you pay for it. Good brands vary. I have used Panamax,belkin,APC, triplite and others with success. Take care.
If it moves, tax it. If it keeps moving, regulate it.
And if it stops moving, subsidize it.
Edited 10/8/2007 3:59 pm by bones
Bones, Fwiw, I would not use breakers as switches. They are not meant to be thrown often and will wear out. Phone and cable lines typically have simple lightning arrestors at point of entry (to the house). This should shunt most of the energy of a strike and hopefully burn out the wire to them rather than the circuit at the end of the loop. Andy
As a retired shift engineer from a Municipal Power Plant I've had more than my share of problems with the "FREE STUFF" as we used to call it. The average lightning bolt is about 300 Kilovolts. A surge protector of any sort doesn't have a chance, an open breaker doesn't mean squat. Just think about the gap a lightning bolt jumps. The off/on/off some of you experience is caused by automatic reclosers on the lines, sometimes the reclosing will create enough of an arc to through a limb off the primaries and all is well. It was common practice to try and reclose a circuit in the plant one time and if the circuit slammed out again it was time to call out the line crew. Not knowing what caused the trip, car/pole, downed wire, Many fried coons, squirrels and once an escaped monkey. So when your power goes out for an extended period of time, by all means call it in. All the help and info you give helps the line"people" locate the problem. Just remember some stupid drunk, or Mother and childs life may depend on your NOT being with power for a short time. Luckily I was never responsible for frying someone.Work Safe, Count to 10 when your done for the day !!
Bruce S.
Your right Bruce, when lightning comes into play and its a direct hit, all bets are off! A lot of the time a fire comes with it! Surges are a different matter. If not too bad you can withstand a surge with a good protector. Its like insurance, don't bother if you can accept the risk. The last APC came with an insurance policy(as long as you kept the papwerwork) It wasn't much about $10,000, but what the hey. Government's view of the economy could be summed up in a few short phrases: If it moves, tax it. If it keeps moving, regulate it. And if it stops moving, subsidize it.
Bruce, another one that use to chap my friends butt, were people using generators during bad weather backwiring into the house without the main throwed! He said he always checked the line even if it was supposed to be de-energized. People don't realize they could kill a guy! Those lineman guys do scarry stuff. Takes a specal breed. He works the highvoltage main lines. I told him he was nuts, but he loves it and says I'm the nut for being in an office! Go figure.Government's view of the economy could be summed up in a few short phrases: If it moves, tax it. If it keeps moving, regulate it. And if it stops moving, subsidize it.
Linemen are nuts, We generated at 13,200 volts with most circuits at that voltage, some of the old circuits were dropped to 4160 volts. The transformer off the Grid was 138,000 Volts. With that transformer breaker open to our system and then opening or closing the mechanical air break was a sight 1' to 1.5' arc. I've saw one Ugly short happen on the 13,200 V buss board, The copper went plasma. Glad I'am retired.Work Safe, Count to 10 when your done for the day !!
Bruce S.
Holy sh*t!You are right, linemen ARE nuts.Peter
Sounds like my friend alright. For fun he trains the new recruits on pole climbing. I mean the big ones. He says he still ocassionally has to go up and help a guy down that freezes at the top. Anyway makes you appreciate that power on demand! Take care.Government's view of the economy could be summed up in a few short phrases: If it moves, tax it. If it keeps moving, regulate it. And if it stops moving, subsidize it.
"Bones,
Fwiw, I would not use breakers as switches. They are not meant to be thrown often and will wear out.
Phone and cable lines typically have simple lightning arrestors at point of entry (to the house). This should shunt most of the energy of a strike and hopefully burn out the wire to them rather than the circuit at the end of the loop. "
You are right about breakers not being used as switches, but I am just a hobbyist, so I don't use my saws that often, and my breakers were $8.00. And it is true that a big hit will jump the bus, but then you have a whole host of problems other than your tools.
If the wiring and feeders, and subs are all nice and new and good grounds all the way around, you have a good chance. I have seen way to many splices, taps, old wiring and grounds placed wrong to not put all my faith that the utility company i.e power/phone/cable that it will be taken care of. The most expensive stuff gets the best, 2nd gets next best etc. I've only seen one APC unit cooked in all the years I've had one, but she was smoked! pretty scary if you ever see one.
Government's view of the economy could be summed up in a few short phrases: If it moves, tax it. If it keeps moving, regulate it. And if it stops moving, subsidize it.
> If the wiring and feeders, and subs are all nice and new and good grounds all the way around, you have a good chance. I have seen way to many splices, taps, old wiring and grounds placed wrong to not put all my faith that the utility company i.e power/phone/cable that it will be taken care of.
Agree. Hopefully pointing this out will warn people who might question their configuration and upgrade if necessary. Its the first place to start before trying to add protection down the line. Reminds me of the people with weak front doors adding one of those cheesy alarm systems and feeling safe in their house.
> I've only seen one APC unit cooked in all the years I've had one, but she was smoked! pretty scary if you ever see one.
Wow, no I have not. I have a few APC units though so I hope I don't ever have to see that. ;)
Andy
> I've only seen one APC unit cooked in all the years I've had one, but she was smoked! pretty scary if you ever see one.
Wow, no I have not. I have a few APC units though so I hope I don't ever have to see that. ;)
The unit that cooked, did it's job. The PC was unharmed, but the APC unit had charcoal at the phone line connection, and it had a definite burnt wiring odor. We called APC and they requested the unit back for examination, and sent us a nice new one. We used the NET7T's at the time (I don't know if thats the current model anymore). I remember when Trip/Lite were king of the hill and the upstart APC came along. It wasn't long till they had really taken over. Government's view of the economy could be summed up in a few short phrases: If it moves, tax it. If it keeps moving, regulate it. And if it stops moving, subsidize it.
I CAN speak from experience. About two months ago my house was hit by lightning. (Lets call it a GIANT power surge.) It blew the downspouts off the house, destroyed 2 TVs and 2 dvd/tape recorders. Wiped out the lawn sprinkler system, blew up one wall switch in the living room and ALL the phones and an answering machine. It DID NOT touch my computers (off at the time), or any of the tools and kitchen appliences. It also wiped outone breaker in the electric box, but did not harm anthing else. Call me lucky, there was no structural damage! I was at the 'other' end of the house when the lightning struck.
So... if the tool was being used (under power) it probably would be wiped out, not to mention the user who was holding onto the tool at the time.
SawdustSteve (in sweltering New York)
Seems like July these past few days.
This story makes me happy that I have a small shop, everything on mobile bases. So nothing stays plugged in exept (until now) my table saw. Thanks for pointing out the silver lining! Chris
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