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Old 12-27-2010, 08:21 PM   #1
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National Grid trusts the general public this much?


I know this should have probably been posted in the off topic section, but I figured I would get more opinions here.

It's extremely windy out so I am gearing up for what could be my first power outage with my home finally wired for a generator backfeed. I was trying to locate power outages in NG's website and came across this
http://www.nationalgridus.com/massel...nerators-1.asp
(second paragraph)

Pretty interesting how they basically say "no transfer switch? just turn the main off then"

At least they tell you not to make a double male cord.

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Old 12-27-2010, 08:35 PM   #2
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This is surprising as it is illegal in some areas. I sure would not want to do it just because I'm trusting myself to not forget. When the power goes out it creates a bit of excitement and you can easily forget things.

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Old 12-27-2010, 09:05 PM   #3
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Originally Posted by Red Squirrel View Post
This is surprising as it is illegal in some areas. I sure would not want to do it just because I'm trusting myself to not forget. When the power goes out it creates a bit of excitement and you can easily forget things.
I backfed without a transfer switch once with an old style CH box that has the main sitting on the bus bars like a normal breaker, I ended up buying a another breaker, disconnecting my main breaker entirely from the panel and tying my genny directly into the panel. It worked in a pinch but I didn't feel good about it.
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Old 12-27-2010, 09:33 PM   #4
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WOW!! That goes against EVERYTHING we know or have ever been told. That is a slap in the face as far as I am concerned.
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Old 12-27-2010, 09:46 PM   #5
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I sent them an E-mail on their site
See what they say
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Old 12-27-2010, 09:48 PM   #6
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Well, I guess their point is if you are going to do something horribly dangerous, you should try to do it safely?

"Kids, don't try this at home..."
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Old 12-27-2010, 09:57 PM   #7
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I sent them an E-mail on their site
See what they say

Please update us.
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Old 12-27-2010, 10:57 PM   #8
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Well, I guess their point is if you are going to do something horribly dangerous, you should try to do it safely?

"Kids, don't try this at home..."
That's probably it. They know people will do it either way, so they figure, if you're going to do it, at least follow this simple rule.

but you'd think they would just straight out say that it's illegal and say what could happen. They could also offer information on how to setup a proper transfer switch.
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Old 12-28-2010, 01:28 AM   #9
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Quote:
If you do not have a transfer switch, make sure your home or office electrical wiring is disconnected from our power lines before you operate your generator. This requires that the main circuit breaker in your electric service panel box is in the OFF position or, in older electric service panel boxes, that the main fuse block is removed. This prevents your generator's electricity from going back into the power lines in the street, which could endanger line crews and your neighbors.
The problem with this so-called "advice" is they have not considered that some homes do not have a single "Main" breaker, but have a split-bus panel instead.

Attempting to backfeed a split-bus panel can indeed be deadly to the line crews as there can be up to 6 disconnecting means, and it would be more likely that a backfeed would be attempted from a dryer outlet, which could be one of those 6.

Paragraph #2 should not even be published!! If you don't have a proper transfer switch arrangement installed, the inside wiring of the building should NOT be connected to a generator!
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Old 12-28-2010, 10:28 AM   #10
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Electrical crews should jumper the hot wire to ground while working on it.

Now this can short out a generator connected to a home system that in turn was not disconnected from the utility lines, if all the other homes and buildings with main breakers still on did not already overload the generator.

The power company (POCO) knows that under the circumstances we are thinking of, there will be people who are not going to be obeying the law. That paragraph at least "asks" them to be careful.

With the medium tension (distribution; primary) hot jumpered to ground up on the utility pole, the resistance from one of your service panel hot terminals, up to the utility pole and through the transformer secondary and back to your panel, is likely somewhere around two ohms. That will attempt an immediate current draw of around 120 amps at 240 volts (or 60 amps at 120 volts) from your generator. (amperes equals volts divided by resistance) Unlike an incandescent lamp or hair dryer, those conductors will not heat up enough to significantly increase the resistance and therefore that current draw will be sustained unless or until your generator breaker trips.
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Last edited by AllanJ; 12-28-2010 at 10:51 AM.
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Old 12-28-2010, 10:39 AM   #11
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National Grid trusts the general public this much?


While extremely dangerous, in reality the home generator would not have enough power to run a neighbourhood and would trip its main breaker. The real danger is if your personal drop lines are down then the generator could energize the home side of the line laying on the ground. This would be a danger to anyone coming near them.
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Old 12-28-2010, 10:56 AM   #12
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Meanwhile, under just the right circumstances, if the lineman did not jumper hot to ground, a generator cranking away in a home could put an 8000 or so voltage on the primary hot wire up on the pole after going through the transformer. Probably less than one ampere but just a few milliamperes will electrocute someone.
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Old 12-28-2010, 12:22 PM   #13
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Once you buy a generator and install the wiring and interlock, you will find you never need it. Make sure you exercise it once and a while.
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Old 12-28-2010, 02:19 PM   #14
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Their response:

Quote:
Dear Customer,

Thank you for your inquiry. Turning off the main breaker during generator use is required and within code. Not only is it required by National Grid, it is required by the NEC, National Electric Code for personnel and citizen safety.

If you would like to clarify your concern we could try to get you a more detailed explanation. What code do you feel as though this procedure violates?
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Old 12-28-2010, 04:51 PM   #15
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Yes, disconnecting the building system from the power company lines during use of a generator is mandatory and within code. But the NEC requires more than that, specifically a means such as a transfer switch that prevents inadvertently reconnecting the building system to the power company lines while still energized by the generator.

Now the NEC does permit interlocks such as cams or levers that immobilize switch handles but which are not foolproof for example if the front cover of the panel together with such interlocks is removed.

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Last edited by AllanJ; 12-28-2010 at 04:55 PM.
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