Threads on electricity bring up the potential for brownouts to fry home appliances.

Question for electrical experts on the forum: is it better, safer, more effective, to unplug things like fridge, computers, ovens etc, or go to the fuse box and throw the master switch so that power is dead throughout the house? This would ensure that nothing gets fried, but does it cause the main fuse to take all the spikes and thus burn it out?

THanks in advance for your

-- powerhog (fridgeisfried@toaster.org), November 10, 1999

Answers

After the main breaker has been switched off, there wont be any spikes, because there wont be any current flowing.

-- Earl (earl.shuholm@worldnet.att.net), November 10, 1999.

Just cut the breakers to the sensitive items. If you can't isolate the item, pull the plug. Normally, the electric lights in a home are relatively insensitive and merely 'brown out'(hence the term). Things like electric motors and electronics are super sensitive to low power.

The breakers in your house will not be harmed by low power but will be thrown by a spike. That's what they are designed to do. If a breaker is off, it is truly off...no connection is made to the power supply....not so with an on=off switch on a computer or 'quick on' tv, etc.

I would make sure I had a couple of Halon or CO2 extinguishers around in case you forget something and we get major spikes instead of brownouts.

"Don't you just love not knowing?"

-- Lobo (atthelair@yahoo.com), November 10, 1999.

Of course, the best person to answer this one would be 'The Engineer' as he works in power. But he'd just say 'We're all compliant and stop talking about those darn PLC's!'. So I guess I'll give it a go.

First let me qualify this: although my degree is in EE, I specialized in Computers and Controls, not Power. I took only what I had to in that area to get by, which was the mandated 'intro' course and the machines course with lab. That having been said, my position is: Main breaker open at or about 5:00pm, CST on Dec. 31, 1999. (I have to give a 'command performance' later that evening at work and wife doesn't want to mess with it.) Main breaker closed on Tuesday, Jan. 4, 2000, always assuming that a) there is any power to be gained from doing so (not a foregone conclusion), and b) I am not watching my neighbors lights go 'bright', 'dark', 'bright', 'dark' the night before, and c) that the radio, tv, newspapers etc. aren't issuing hourly bulletins about when the power will be back on.

'Nuff said?

-- just another (another@engineer.com), November 10, 1999.

the spikes would have a worse affect on the main breaker or fuse if the power was left on to some things. And things can be fried by lightning when the main breaker is pulled.

The individual items will always be better protected if totally disconnected with as short a cord left on them as possile. Leaving them plugged in means that a spike from lightning or some mis-wired or faulty equipment can cause a spike of electricity between the neutral and ground lead. This might have bad affect or none at all.

As far as computers and other delicate electronics that are plugged into the power grid as well as a phone line or cable service or both, a voltage differential between the phone line and any of the power leads can cause major damage. Power, phone and cable should all have grounding and surge protection bonded together at a single house entrance. If the different services are grounded at different points around the house, the grounds can be at several hundred or even thousands of volts difference. This has actually caused a number of deaths.

-- tree (thetrees@bigfoot.com), November 10, 1999.

As an aside to the self-protection issue, if the power goes off then TURN OFF YOUR APPLIANCES. It's not just your home that suffers from spikes, it's the grid too. The last thing Mr Grid wants is to have a massive drain on it the second it comes back up.

-- Colin MacDonald (roborogerborg@yahoo.com), November 11, 1999.

If you were a smart man, you would disconnect all power and phones from the outside world untill you can determine that there are no more problems than normal. 5pm your time, seems like a good number.

-- FLAME AWAY (BLehman202@aol.com), November 11, 1999.

This family will disconnect from the grid an hour early and go on the generator for the rest of the evening so we can watch the world light up or go dark...whatever! I had hopes of staying on the computer and reading the reports coming in from around the world, but that means leaving phone lines connected. Is that a concern other than from lightening? Fried computer is a well known native dish in Florida. I have cooked two computers and two fax machines in 5 years. All have been fried, per autopsy, through the phone lines.

Taz

-- Taz (Taz@aol.com), November 11, 1999.

"Cutting the breaker" means what, exactly? My fuse box was switched to a circuit breaker. Does this mean turning off the breakers to the particular lines?

I'm glad this thread came up, because I am currently trying to decide what I should do. From various threads in the archives, it seemed like a whole house surge protector and then line conditioners where I was particularly concerned about low voltage was the answer.

I do not want to have to go entirely offline for a few days at rollover if it turns out there was no reason to during that time. My wood stove simply won't heat my entire house properly. (I can manage, but it would be really tough on my elderly parents.) I am most concerned about my furnace motor (and secondarily my refrigerator) being fried, so even if I unplug or unbreak everything else, I still need to have a plan for these appliances. And besides, dirty power throughout much of 2000 seems like a possibility.

So, could we have some definite answers for how to protect the stuff that MUST (e.g., will) stay in use?

-- Brooks (brooksbie@hotmail.com), November 11, 1999.

Here's a twist on this problem.

We'll be away from our apartment for several weeks before and after the rollover. I had planned on disconnecting the stereo, TV, computer etc., before leaving, but had planned on leaving the refrigerator plugged in. Is there a potential fire hazard here? And is it important to disconnect the phones?

Thanks for a useful thread!

-- Midas (midas_mulligan_2000@yahoo.com), November 11, 1999.

I have seen my submersible(3-wire)pump DOUBLE its current during an artifially induced undervoltage. Under such conditions, the thermal cutout in such pumps will make it trip. I will restart when cooled down. It MAY do that for many cycles, but it wasn't designed to operate that way. (The breaker for the pump does NOT protect the pump from this condition, it protects the wiring.) Be aware of the effect if your water supply becomes intermittent and there is a brownout. Radio Shack sells expanded scale voltmeters (plug-into-outlet). VERY good for a quick assessment of what your line voltage is at any time.

-- WFK (kb2fs@mindspring.com), November 11, 1999.

The problem with answering this question is that brownout has taken on different meaning then the original. In the Utility business a brownout is a controlled reduction in voltage of 5%. Usually this is done in the summer because of air conditioning loads. The brownout is rotated among areas so that no one area has reduced voltage for a prolonged period of time. If this is the kind of brownout you mean than you shouldnt have to protect any of your equipment by unplugging it. As an example you might be at work when your home is in an area that is undergoing a brownout. You dont have to rush home to unplug your appliances. Usually most equipment can take this 5% reduction in voltage without undergoing any harm.

Brownouts dont cause spikes. That is mixing apples and oranges so to speak.

You should have a surge protector on your computer and phone line. I like one with a built in back up battery so that if the power does go out I have time to save my work and shut down the computer in an orderly way.

Spikes: When you are talking about a spike the question is how much of a spike and for how long? Tree is absolutely correct that if you have lightning hit your house or the line that feeds your house (within a half mile or so) you run a very real risk of damage regardless of whether the breaker is pulled or not. Thats because the voltages from lightning are high that they can jump over the air gap provided by opening the breaker. However lighting also is usually very high frequency and it quickly becomes attenuated so that if the stroke is say a few miles from your house the chance of damage is slight. Ive seen photographs of lightning hitting distribution lines and it will run down the line before finding a weak spot in the insulation to arc to ground.

As a general rule of thumb I would not unplug anything that has a motor in it such as a refrigerator, furnace etc. These are built to withstand the 5% low voltages. If there are any problems such as loss of synch or swings the chances are you would be in the dark very quickly.

-- The Engineer (The Engineer@tech.com), November 12, 1999.

---well, I've gone through the stack of wood, and all dated non compliant pine and oak has been replaced. now the embedded handle in the water bucket has been duct taped. still have to put in 4 digit air into the bicycle tires to get them up to snuff, but we are "on track" to have that done by 12/31/1999. the extensive supply lines from the garden to the stove have been cleared of all debris and dog poop which might have caused delays in shipping fresh foodstuffs to the consumer(me). --all in all, everything seems to be y2k-ok here...........

-- zog (zzoggy@yahoo.com), November 12, 1999.

From: Y2K, ` la Carte by Dancr (pic), near Monterey, California

When I have seen the term "rolling brownout" used in reference to Y2K, it has been accompanied with an description that basically indictes plans to totally cut the electricity except for perhaps four hours per day... enough to supposedly keep food in refrigerators from spoiling. What kind of damage might we expect to computers and appliances from this?

-- Dancr (addy.available@my.webpage), November 12, 1999.