This is way off topic, but related to a recent thread. I have a 5500 watt generator that might see some usage tonight or tomorrow. In the 2002 ice storm I fed the 240 out of the generator and into my ac 2 pole breaker to feed the electrical panel in the house. I threw the main while doing this and had no problems. Now, thinking about the coming storm I was looking at the possibility of doing this again. Everything you read on the the Internet says you are crazy for doing this and risk frying your generator, killing a linesman, or burning down your house. My question for you electrical whizzes is if I absolutely, positively remember to throw the main when doing this, what are the real dangers then. Is it just warned against because someone _might_ forget to throw the main or are there dangers even if the main is thrown.
TIA,
Brad
I'm in no way an expert, but I have heard about several people doing this w/o any consiquinces. Also From what I understand even if you forgot to throw the main, it shouldnt be a real problem unless a lineman happens to be working nearby, this is what is know as feeding the grid, pushing power back to the electrical grid. Lots of off grid solar equipped people are doing this, and in most cases get a check from their power company for supplying power back to the grid. Also I heard a story about the Sprint being asked to run their generators at the campus during the day to generate their own power, and at night connect to the grid and feed power back to the power company. But that is all hearsay.
So in my _nonexpert opinion_, as long as you disconnect the main, you shouldnt have any problems powering your home.
---------- Forwarded message ---------- From: Brad brad@bradandkim.net Date: Tue, 04 Jan 2005 14:35:19 -0600 Subject: OT: generator for ice storm To: kclug@kclug.org
This is way off topic, but related to a recent thread. I have a 5500 watt generator that might see some usage tonight or tomorrow. In the 2002 ice storm I fed the 240 out of the generator and into my ac 2 pole breaker to feed the electrical panel in the house. I threw the main while doing this and had no problems. Now, thinking about the coming storm I was looking at the possibility of doing this again. Everything you read on the the Internet says you are crazy for doing this and risk frying your generator, killing a linesman, or burning down your house. My question for you electrical whizzes is if I absolutely, positively remember to throw the main when doing this, what are the real dangers then. Is it just warned against because someone _might_ forget to throw the main or are there dangers even if the main is thrown.
TIA,
Brad --
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This is what I thought as well, but if you read posts on the net about it, people get their heads chewed off by people who obviously know more than I do about electricity. I am hoping there is also no danger of fire or anything at my home. It is looking like I may need to do this given the looks of things.
Thanks,
Brad
On Tue, 2005-01-04 at 15:51 -0600, Ben Kelley wrote:
I'm in no way an expert, but I have heard about several people doing this w/o any consiquinces. Also From what I understand even if you forgot to throw the main, it shouldnt be a real problem unless a lineman happens to be working nearby, this is what is know as feeding the grid, pushing power back to the electrical grid. Lots of off grid solar equipped people are doing this, and in most cases get a check from their power company for supplying power back to the grid. Also I heard a story about the Sprint being asked to run their generators at the campus during the day to generate their own power, and at night connect to the grid and feed power back to the power company. But that is all hearsay.
So in my _nonexpert opinion_, as long as you disconnect the main, you shouldnt have any problems powering your home.
On Tue, 4 Jan 2005, Brad wrote:
This is way off topic, but related to a recent thread. I have a 5500 watt generator that might see some usage tonight or tomorrow. In the 2002 ice storm I fed the 240 out of the generator and into my ac 2 pole breaker to feed the electrical panel in the house. I threw the main while doing this and had no problems. Now, thinking about the coming storm I was looking at the possibility of doing this again. Everything you read on the the Internet says you are crazy for doing this and risk frying your generator, killing a linesman, or burning down your house. My question for you electrical whizzes is if I absolutely, positively remember to throw the main when doing this, what are the real dangers then. Is it just warned against because someone _might_ forget to throw the main or are there dangers even if the main is thrown.
Just don't feed your entire house off a 18 guage extension cord!
I'm used to fixing electrical disasters at work, so I have an eye for what doesn't work. Use connectors rated for at least the circuit breaker rating, use heavy guage wire (10 guage is plenty for 30 amp overload) and route your wiring neatly and you should have any problems.
I'm not sure if a generator hooked up to a live circuit will sync or not. The peaking generators I worked with only kicked the main breaker when it was synced at engine temperature. I guess if a circuit breaker the size of a television can protect a 1,600,000 watt load if it was out of sync, I don't see your house blowing up over an comparibly insignificant 5,500 watts.
If you are feeding your neighborhood, your generator's circuit breaker is likely to trip. That's a large load. Worst case you could burn out every electrical device in your neighborhood, because all their electric motors are off frequency and undervoltage.
If you have a voltmeter that measures frequency, be sure to check that it doesn't get too carried away from 60Hz and 120 volts. AC motors syncronize to the frequency. 70Hz may start to magnetically slip inside and burn up, especially if the voltage hasn't been increased to match the frequency curve. If the generator's frequency can't be controlled, you will be witnessing a fun science experiment in action.
UPS supplies are nice with a generator. Have them next to important things like your televisions and lights if you need to refuel. If you have a really big UPS, you can cover the whole house. Such units complete with switchgear are becoming popular surplus items. One of the guys on the list gave me a few 10KVA units (3,000 pounds each!) They recreate a perfect sine wave at an exact voltage and frequency of your choice, regardless how wild your generator gets.
Its nice running everything in the house when the power is out. Being in the dark with the one you love in front of the fireplace may be romantic, but it becomes a chore real quick!
-=Duane http://dattaway.org
Just don't feed your entire house off a 18 guage extension cord!
I'm used to fixing electrical disasters at work, so I have an eye for what doesn't work. Use connectors rated for at least the circuit breaker rating, use heavy guage wire (10 guage is plenty for 30 amp overload) and route your wiring neatly and you should have any problems.
I'm not sure if a generator hooked up to a live circuit will sync or not. The peaking generators I worked with only kicked the main breaker when it was synced at engine temperature. I guess if a circuit breaker the size of a television can protect a 1,600,000 watt load if it was out of sync, I don't see your house blowing up over an comparibly insignificant 5,500 watts.
If you are feeding your neighborhood, your generator's circuit breaker is likely to trip. That's a large load. Worst case you could burn out every electrical device in your neighborhood, because all their electric motors are off frequency and undervoltage.
If you have a voltmeter that measures frequency, be sure to check that it doesn't get too carried away from 60Hz and 120 volts. AC motors syncronize to the frequency. 70Hz may start to magnetically slip inside and burn up, especially if the voltage hasn't been increased to match the frequency curve. If the generator's frequency can't be controlled, you will be witnessing a fun science experiment in action.
UPS supplies are nice with a generator. Have them next to important things like your televisions and lights if you need to refuel. If you have a really big UPS, you can cover the whole house. Such units complete with switchgear are becoming popular surplus items. One of the guys on the list gave me a few 10KVA units (3,000 pounds each!) They recreate a perfect sine wave at an exact voltage and frequency of your choice, regardless how wild your generator gets.
Its nice running everything in the house when the power is out. Being in the dark with the one you love in front of the fireplace may be romantic, but it becomes a chore real quick!
-=Duane http://dattaway.org
Thanks Duane. I am running about 10-12 feet of 10 gauge water resistant wire in a window and into the ac breaker. I will have the black wire connected to one breaker, the red wire into the other breaker, and both the green and white connected to the grounding block in the box.
When I throw the main, am I totally off the grid? Is there any chance that poor wiring in the house could make this unsafe? I have a new 120 amp service that was inspected by the city, but I cannot swear all the wiring in the house is the greatest...it's an older home.
BTW, I am the one on the list that gave you those UPS's...sounds like they are getting good use.
Thanks,
Brad
On Tue, 4 Jan 2005, Brad wrote:
Thanks Duane. I am running about 10-12 feet of 10 gauge water resistant wire in a window and into the ac breaker. I will have the black wire connected to one breaker, the red wire into the other breaker, and both the green and white connected to the grounding block in the box.
When I throw the main, am I totally off the grid? Is there any chance that poor wiring in the house could make this unsafe? I have a new 120 amp service that was inspected by the city, but I cannot swear all the wiring in the house is the greatest...it's an older home.
BTW, I am the one on the list that gave you those UPS's...sounds like they are getting good use.
When you turn off the main, your circuit to the grid is off. The National Electrical Code specifies a transfer switch and something else if I remember right. Yours and mine may work well in an emergency. Hopefully one day I will get the money for a proper transfer switch and other things to meet the Code. Its a well written guide that almost eliminates any possibility of accidents.
Oh thank you! I recognized your name after I sent the email! This UPS has been very nice during power outages. One of these days, I'm going to add solar power to this project. If you ever need any help throwing large stuff in the dumpster again, please let me know. ;)
-=Duane http://dattaway.org
Duane Attaway wrote:
On Tue, 4 Jan 2005, Brad wrote:
Thanks Duane. I am running about 10-12 feet of 10 gauge water resistant wire in a window and into the ac breaker. I will have the black wire connected to one breaker, the red wire into the other breaker, and both the green and white connected to the grounding block in the box.
When I throw the main, am I totally off the grid? Is there any chance that poor wiring in the house could make this unsafe? I have a new 120 amp service that was inspected by the city, but I cannot swear all the wiring in the house is the greatest...it's an older home.
BTW, I am the one on the list that gave you those UPS's...sounds like they are getting good use.
When you turn off the main, your circuit to the grid is off. The National Electrical Code specifies a transfer switch and something else if I remember right. Yours and mine may work well in an emergency. Hopefully one day I will get the money for a proper transfer switch and other things to meet the Code. Its a well written guide that almost eliminates any possibility of accidents.
Oh thank you! I recognized your name after I sent the email! This UPS has been very nice during power outages. One of these days, I'm going to add solar power to this project. If you ever need any help throwing large stuff in the dumpster again, please let me know. ;)
-=Duane http://dattaway.org
Well- my comments would be partially redundant save for my just having used parts of what I preach . The furnaces at the campground have been fitted with standard 3 prong 15A plugs that are usually plugged into a socket assigned to it . No expensive transfer switch or chance of a back feed - simply unroll a heavy enough extension cord- Almost took advantage of a camper with a genset tonight" If the power stays off I may beg to plug into your genny"
Most rooms have a cheap flashlight from walmart or target of the "comes on when power fails type " . I have a 1500 W inverter fitted with car jumper cables on it's input side . Had tonight's power outage- from 2am till 345 or so been longer I would have hooked it up to a car -to run each furnace long enough to keep pipes and us from freezing .Hardly ideal or painless but bare survivability beats the alternatives . Hacking standard UPS boxes to allow external batteries demands caution as the battery circuit is often "hot" to earth ground! The automatic flashlights turned possible panic into a mild annoyance . Knowing we had a heating backup if the power stayed helps keep calm too , Now to be fair- I was VERY envious of our overnight camper who had his genset autostart on the power failure ! That autostarting genset being what woke us up to hear the silence of no power .
This experience may make me speed up the Biodiesel project . Several vendors are selling former rail reefer power units based on the Detroit diesel 2-71 engine and a 30A 3 phase alternator head . If connected properly one of these could keep a barely normal lifestyle . Cost - 1 to 2 K genset itself and about the same to take it from a skid mounted configure to a seamless autostart with transfer switch . NOT cost effective compared to my ancient tripp-lite square wave inverter and running a car . Used on Biodiesel in making the meter run backwards may have er- Potential . Watts the point in missing a pun in an ot post anyways ? To make the Biodiesel and generator thread back to topical we COULD use Linux to design the systems and as control software . Even a future issue of handshaking with a utilities SCADA system to isolate an "island" of one or more distributed generators - As some -see Sprint campus etc may have enough extra to power some priority neighbors- Gas stations , grocery stores etc -how many minutes of an hour do furnaces need to run to keep average houses at 50F ? Thus rotating feeds into residential areas if reclosers could be so programmed ? Hmn - the nontrivial modeling of such schemes cries out for a Linux cluster !
Oren
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Ben Kelley -
Brad -
Duane Attaway -
Oren Beck