While at the local electrical supply house recently, I overheard a DIYer asking the counter man how to install a residential generator transfer switch. To my surprise, the counterman began to explain the connections to him. Then I got to wondering.. If the DIY guy mistakenly miswired the utility and common connections, and properly made the generator connection, upon throwing the transfer switch and starting the generator, the utility transformer would be back-fed, thereby providing primary voltage to the transformers input terminals and potentially harming(or worse)a utility worker. I thought about intervening, but chose not to. Any thoughts?
I would have said something... but I'm kinda out front with that sort of thing... Consider me cruel, but I would've talked real fast, cite some code and used big words in hopes that they would consider it above their heads and call for help.
My supplier has a sign that states to contact your local electrician because they do not give advice... although they do give some advice, like which materials to buy and use.
-Virgil Residential/Commercial Inspector 5 Star Inspections Member IAEI
You're right about backfeeding a transformer if the transfer switch gets connected incorrectly - leading to possibly killing a lineworker. That would really happen if a transformer was fed from a generator during a loss of utility power.
It's hard for me to keep quiet when suggestions are tossed out to DIY'ers - especially at home centers when the information is wrong. But after having to either argue with the info slinger, or getting the 2nd degree from the DIY'er, I have built up a reluctance to get involved. Believe me, it's hard to just walk away when someone is at a home center asking advise from the store staff person. Once in a while the person in the electrical section will be sharp enough to really assist - this is maybe 25% of the time [from what I have seen].
Sure wish I could tell you without a doubt to take charge of the situation and be absolutely sure the person does it right - but as we all know, the only way this can be done is to install it yourself.
There are many DIY'ers out there which have the ability to perform electrical installs safely, for which I am personally proud of them for. When a competent DIY'er has been biased by someone "hotshotting" information which is incorrect, then the whole thing is doomed!!
Scott " 35 " Thompson Just Say NO To Green Eggs And Ham!
>leading to possibly killing a lineworker. The outage would have to be a broken wire on both sides of the transformer, or on one side for the last house on that feeder.
The home generator would not be able to energize houses miles away unless it was really huge.
However, with the numbers of co-gen, back up gensets, and net metering installations, plus wire for different companies and of different voltages on the same pole, a lineman is improperly supervised if he grabs an ungrounded wire assuming that the wire has to be dead.
A smart lineman should assume that just out of sight a 100 KV line has fallen on the line he is about to grab.
Around here they run a stake into the earth for every conductor on both sides of the area to be serviced. And then they clamp a wire from the stake up to the conductor.
That should be enough to extinguish the 1-12 amps from home generators.
Now if the lineman is replacing the DIY's transformer and he assumes that the DIY's backup generator is not energizing the transformer or service drop... he could get zapped big time.
Originally posted by sparky: The complaint on one service call was that the genny kept stalling out, on closer inspection, the genny was feeding right into the utility side. I found the 'stall' phenomenon interesting.
1/2 my biz comes from the DYI'ers, who would have pulled it off if closer attention and/or investigation had occured.
It's a long haul to gain your stripes in this trade, but we need to view the home depot or lowe's electrical seminar's, time life readers and hardware store DYI'ers in a certain light.
The powers that be do, or all electrical merchandise would not be available publicly.
The generator was probably stalling due to feeding the 3 or 4 other homes connected to transformer secondary.
[This message has been edited by Redsy (edited 06-29-2001).]