Not quite. A transfer switch prevents the possibility of
having both sides connected at the same time.
Depends upon your definition of a competent person. Joe-blow
may certainly think he's competent because he knows how to
do it as you described above. I think I'm competent and
that's why my generator hookup is to code requirements - via
a transfer switch and proper sized cable and connectors.
My bad, should have read 'transfer switches'
seems to go right over their heads.
Agreed, but depends upon your definition of an emergency
situation. If someone is on a heart-lung machine, or
something of that nature, and a back-up power source is not
available and a generator must be brought in to provide
power then I would consider that to be an emergency
requirement. But a power outage for a few hours is not a
real emergency for most homes, an inconvenience perhaps, but
not an emergency.
And how do you define a permanent installation? I have a
portable generator that gets connected through a transfer
switch to the house during extended power outages. When line
power comes back on the generator gets disconnected and
rolled back into the shop. This is not a permanent
installation, but code still requires it be connected via a
If a person has a generator on hand and intends to use it
during power outages then that person should have the means
to connect it properly and safely..
Well, that is what they attempt to do. They do however fail on occasion.
Your generator hookup is a permanent installation, even if the generator
itself is not part of the installation. Pretty common to see at telecom
sites as well, permanently installed transfer switchgear and a big ol'
IEC style plug on the outside of the building (or ped) to connect a
towable generator to when needed. Allows a smaller fleet of towable
generators to service multiple sites and also allows central storage and
servicing of those generators.
Also quite common to see a small Honda generator chained to the base of
a pole and powering a cable TV power supply. No transfer switch here,
just switch of the main disconnect and wire in the extension cord.
An isolating transfer switch would be one type. Also have less common
make before break paralleling transfer switches.
Everything is relative, but in an ice storm where there is a real risk
of damage from frozen pipes in a short time period that would meet my
definition of emergency. If there are children or elderly who are not as
able to handle the cold as a typical healthy adult that would be an
emergency. In hot weather were some people would be at risk without A/C.
You have a permanent installation of generator connection facilities.
The generator itself need not be a part of that installation.
And that means can include the knowledge of how to make a safe temporary
connection for the one or two times a year they may need it. If it's a
fairly frequent occurrence then it justifies at least a basic transfer
switch installation, once or twice a year does not if the user is
You can get along without a transfer switch as long as
you never make a mistake, but it only takes one mistake
to cause you to wish you had installed one.
I ran a home gen for several years without a transfer
switch - I had the gen cord (with male plug) wired into a
spare two-pole breaker and an air-conditioner type
disconnect in the garage in line with the cord so that the
possibility of a 'suicide cable' configuration was
diminished. I knew what to throw/connect/disconnect when
and everything worked fine... I was confident with my
knowledge and ability.
Well, during one power outage I did something in the
wrong sequence and all it did was trip the breaker on
my generator, but it scared me *big time*. I immediately
bought a new one of these
(http://www.connecticut-electric.com/10-12K1.asp ) on eBay
for about half of the store price, selected the circuits
to use with it and installed it properly. Now, even my
wife can get the backup power going (well, almost): She
fried the garage door opener and several other items by
not having the twist-lock plug shoved in completely into
the generator - it was thus connected without a neutral
and several items in my house took offense to this
And that inexpensive little link bar is too much trouble to install?
FYI, tags alone don't meet the OSHA requirements for tag-out/lock-out in
residential setting. Tag-out only works if all employees/personel that have
access to the area receive basic tag-out training. Otherwise, locks are
But that's OSHA. I'm sure you'll argue that such rules don't apply in an
emergency (except to the lineman that forgets a step in their procedure and
ends up dead). BTW, is powering up your home to save $200 of beef in the
freezer, or watch TV an 'emergency'??
Depends, as long as you have adequate panel space then it's not too much
trouble. The mechanical link bar kits require the breakers to be
positioned opposite each other so you can't use the standard top center
main breaker position. Since the link bar requires one of the breakers
to be off at all times that means you have to have a dedicated back feed
Ultimately you need four panel spaces for the two breakers and need to
install a dedicated back feed outlet. Still a cheaper and easier option
than any of the standalone transfer switches. Likely something I will do
when I replace the POS Stab-Loc panel in my current house with a decent
40 space QO panel.
Actually OSHA rules don't apply at all in a non-commercial setting. OSHA
only applies to commercial contractors working in a residential setting,
not to homeowners.
Depends on the situation and it's not as clear cut as you might think.
In most circumstances it probably doesn't qualify as an actual
emergency, more of an urgent property protection situation. However
consider the case where you live in the boonies and are getting the
100yr blizzard of doom. In that situation where you may well not be able
to reach a store for days or weeks, preserving your food supplies and
watching TV for news reports and info would certainly qualify as an
Stop spreading dangerous misinformation. Backfeeding generators can and do
A few of the many, many links that warn of this hazard.
You are a hazard.
There is absolutely no misinformation in what I posted. The links you
list border on misinformation in their omissions.
I indicated that if you screw up and back feed the mains you will
provide an opportunity for a careless lineman to kill themselves, not
kill them directly. This is a *fact*. A lineman following established
procedures will *not* be killed by a back feeding generator.
As I've noted, every case I've seen where a lineman was "killed by an
improperly connected generator" has clearly shown that the lineman in
question did not follow proper procedures. If you have references to a
case where a lineman followed procedures and was killed by an
"improperly connected generator" I'd like to see it.
I bet you also believe you can't put metal in a microwave oven...
What color is the sun in your little world there?
Do you not know that when you put 240V back through the transformer, it
energizes the lines to 7200 Volts? Do you know how little current it takes
to kill someone at such a voltage? Your comments are stupid and
irresponsible. You just have to admit you're wrong sometimes, and there's
no amount of explaining that can save you.
I'm well aware of how a transformer works, in fact I was the only one to
pass my power distribution course with a perfect score (all weekly
tests, mid term and final 100% correct).
My comments are 100% factually accurate. Please provide specific
examples with references to what you think I am incorrect on.
The bottom line is that you can not kill a lineman by inadvertently back
feeding the mains. In order for the lineman to be killed he must also
not follow established procedures for his work.
The lineman issue is potentially a problem but the real thing that
keeps you from backfeeding the grid is the grid itself. When your tiny
little generator hits your neighbor's A/C units and whatever else they
still have on, your generator's breaker will trip. On my street there
are about a dozen houses fed from a common secondary set and 4
transformers, all in parallel. It would take a very big genset to even
bump that line. Unless the primary is broken on your dead end street,
very close to your house, you will also be trying to feed all the
I'm lucky in that I share a 50KVA transformer with one neighbor.
The numerous issues in even creating a situation that could allow a
lineman to kill himself aside, the bottom line is that it will take
careless actions on the lineman's part for an injury to occur. Your
careless back feeding of the mains in the rare case where that is even
possible will not be the cause of death, it will only be an enabling
Arguing about the details on Usenet is easy. But, even
if you are technically "right," (and, legally, that
might not be good enough), would you really want to
risk arguing the matter in court, AFTER someone has
died, and the utility and that court are looking to
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