> | phil-news-nospam@ipal.net wrote:

> |> |> I can say that because I don't actually need to know the test voltage in

> |> | order

> |> |> to do the right thing ... which is to never, ever, design it into a
system
> |> |> where any design voltage applies will be above the _rated_ voltage. It
is
> |> | the

> |> |> _rated_ voltage that I design to, not the _test_ voltage. So I do not

> |> | need to

> |> |> know the test voltage to do the design right; I only need to know the

> |> | rated

> |> |> voltage.

> |> | So your car has 14V bulbs and relays? :)

> |>

> |> I'm not talking about cars. I'm talking about a home with a generator in

> |> the system separated from a live utility by a single main breaker.

> |

> | So now it's a single breaker between the utility and the generator?

>

> It always has been. This is a case where the breaker supplying generator power

> into the panel bus is in a closed state. So that breaker is not counted as a

> breaker with a voltage across it.

Now anything that's on isn't there anymore and doesn't count?

How about this setup:

utility power bolted to a buss bar as well as the generator. All circuits
in the home bolted to that. no breakers at all.

Now there's no airgaps to jump, and never a potential 480 volts anywhere.

all problems solved. Everybody wins.

I just cancelled out the breakers that were on, since they're not there.

Posted by on July 12, 2008, 1:13 am

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On Fri, 11 Jul 2008 21:40:51 +0000 (UTC) Cydrome Leader
| phil-news-nospam@ipal.net wrote:
|> On Fri, 11 Jul 2008 02:21:14 +0000 (UTC) Cydrome Leader
|> | phil-news-nospam@ipal.net wrote:
|> |> |> I can say that because I don't actually need to know the test voltage in
|> |> | order
|> |> |> to do the right thing ... which is to never, ever, design it into a
system
|> |> |> where any design voltage applies will be above the _rated_ voltage. It
is
|> |> | the
|> |> |> _rated_ voltage that I design to, not the _test_ voltage. So I do not
|> |> | need to
|> |> |> know the test voltage to do the design right; I only need to know the
|> |> | rated
|> |> |> voltage.
|> |> | So your car has 14V bulbs and relays? :)
|> |>
|> |> I'm not talking about cars. I'm talking about a home with a generator in
|> |> the system separated from a live utility by a single main breaker.
|> |
|> | So now it's a single breaker between the utility and the generator?
|>
|> It always has been. This is a case where the breaker supplying generator
power
|> into the panel bus is in a closed state. So that breaker is not counted as a
|> breaker with a voltage across it.
|
| Now anything that's on isn't there anymore and doesn't count?

If you want to know how many breakers have a voltage across the contacts,
you don't consider closed breakers.

| How about this setup:
|
| utility power bolted to a buss bar as well as the generator. All circuits
| in the home bolted to that. no breakers at all.
|
| Now there's no airgaps to jump, and never a potential 480 volts anywhere.
|
| all problems solved. Everybody wins.
|
| I just cancelled out the breakers that were on, since they're not there.

Now you're just being silly. You know that won't work safe at all.

--
|WARNING: Due to extreme spam, googlegroups.com is blocked. Due to ignorance |
| by the abuse department, bellsouth.net is blocked. If you post to |
| Usenet from these places, find another Usenet provider ASAP. |
| Phil Howard KA9WGN (email for humans: first name in lower case at ipal.net) |

Posted by daestrom on July 8, 2008, 8:26 pm

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phil-news-nospam@ipal.net wrote:

> On Mon, 07 Jul 2008 08:11:46 -0400 Mike Copeland

>>>

>>> Really? Quite a few authorities such as UL and the NEC tend to

>>> disagree with you. Consider this fully approved gadget

>>>

>>> http://www.interlockkit.com/intro2.htm

>> That's kind of neat....looks like a sideways version of the device on

>> Manual Bus Transfer I remember from the Navy. Useful for those that

>> don't know what they are doing.

> I've seen one of those in someone's home several years ago. It was

> not like

> this one ... in looked more durable than the one on this page, and

> yet it was BROKEN (actually bent sideways enough to allow

> simultaneous closure of both

> of the controlled breakers).

> If they made this thing on the inside of a frame it would be more

> durable.

> OTOH, a frame would not work well with the way the illustrated panel

> is

> layed out.

> I still think this is a poor solution for multiple reasons. I do

> know that

> UL does test at a sufficient voltage level where the breakers are

> going to

> be able to handle that. But they are unwilling to RATE breakers at

> the 480

> volt level despite that.

> Since I said "multiple reasons" I suppose I should give more.

> Another is

> that the "handyman" seeing this in one location will figure he can

> set it

> up in his own location, sans the interlock (believing he will

> "remember"

> to open one before closing the other). And yet another is the fact

> that

> this arrangement, especially when tried on a subpanel (which might be

> done

> to limit the circuits powered by the generator), can result in a

> ground loop

> path for neutral currents (e.g. two or more points where the neutral,

> which

> is not switched, is bonded to the ground). If the generator has such

> a bond, then you have a problem. If you might want to safely test

> load the generator when utility power serves most of the house (e.g.

> keep the two supplies and

> two load sets isolated), you will need a generator neutral to ground

> bond.

I think you can also just not switch the neutral anywhere throughout the
subpanel and rely on the main service panel neutral-ground bond.

ISTR this is one way of tieing in a generator. Leave the generator
ground-neutral unbonded and hard-wire the neutral throughout so it isn't
switched.

If you *do* switch the neutral in the transfer switch (i.e. use 3 pole
switch) then you *must* bond the generator neutral and ground at the
generator.

Either way you only have neutral and ground connected together at one point
(at a time).

daestrom

> There are some panels (seen them in a Schneider catalog) that have a

> double

> feed breaker arrangement where two molded case breakers can be placed

> side by side. The framed sliding interlock would be easier that way

> as it would not

> have a contorted path.

> Still, I much prefer the transfer switch, and prefer one that

> includes switched neutral with the correct sequencing.

Why do you think switching the neutral to be important?

daestrom

Posted by on July 9, 2008, 12:57 am

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wrote:

| I think you can also just not switch the neutral anywhere throughout the
| subpanel and rely on the main service panel neutral-ground bond.

That would be the simplest way.

| ISTR this is one way of tieing in a generator. Leave the generator
| ground-neutral unbonded and hard-wire the neutral throughout so it isn't
| switched.
|
| If you *do* switch the neutral in the transfer switch (i.e. use 3 pole
| switch) then you *must* bond the generator neutral and ground at the
| generator.

Right.

| Either way you only have neutral and ground connected together at one point
| (at a time).

Exactly.

| daestrom
|
|> There are some panels (seen them in a Schneider catalog) that have a
|> double
|> feed breaker arrangement where two molded case breakers can be placed
|> side by side. The framed sliding interlock would be easier that way
|> as it would not
|> have a contorted path.
|>
|> Still, I much prefer the transfer switch, and prefer one that
|> includes switched neutral with the correct sequencing.
|>
|
| Why do you think switching the neutral to be important?

It would make it easier to have some loads switch to the generator while still
leaving other loads on utility, when testing or exercising the generator. Of
course you can have both operating at the same time with a common neutral and
one ground bond. But that would mean a rather complex panel to achieve it.
I have not seen any panel that can do that. It would have 2 transfer switches.
That leaves the only option being to separate things into 2 panels, and thus
the issue of "now where" to bond neutral to ground upstream and that would have
to be separate for each source.

I'm going to end up having a separate main cutoff switch for utility power,
anyway. From there it will go to a surge protection and RFI filtering device
or devices, and then to the branch panels. I could put a transfer in at the
main cutoff, but that limits me to switch everything to utility or everything
to generator, and no in between. Instead, there will be a separate "main" for
the incoming generator, and two transfer switches. Bonds will be at the main
cutoff switches, so the transfer switches have to switch neutral to avoid the
double ground path.

--
|WARNING: Due to extreme spam, googlegroups.com is blocked. Due to ignorance |
| by the abuse department, bellsouth.net is blocked. If you post to |
| Usenet from these places, find another Usenet provider ASAP. |
| Phil Howard KA9WGN (email for humans: first name in lower case at ipal.net) |

Posted by Solar Flare on July 13, 2008, 9:54 pm

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The neutral must be switched in Canada. Those generator panels that Home
Depot sells have been removed from the shelves and replaced with neutral
switching breakers.

> phil-news-nospam@ipal.net wrote:

>> On Mon, 07 Jul 2008 08:11:46 -0400 Mike Copeland

>>>

>>>>

>>>> Really? Quite a few authorities such as UL and the NEC tend to

>>>> disagree with you. Consider this fully approved gadget

>>>>

>>>> http://www.interlockkit.com/intro2.htm

>>>

>>> That's kind of neat....looks like a sideways version of the device on

>>> Manual Bus Transfer I remember from the Navy. Useful for those that

>>> don't know what they are doing.

>> I've seen one of those in someone's home several years ago. It was

>> not like

>> this one ... in looked more durable than the one on this page, and

>> yet it was BROKEN (actually bent sideways enough to allow

>> simultaneous closure of both

>> of the controlled breakers).

>> If they made this thing on the inside of a frame it would be more

>> durable.

>> OTOH, a frame would not work well with the way the illustrated panel

>> is

>> layed out.

>> I still think this is a poor solution for multiple reasons. I do

>> know that

>> UL does test at a sufficient voltage level where the breakers are

>> going to

>> be able to handle that. But they are unwilling to RATE breakers at

>> the 480

>> volt level despite that.

>> Since I said "multiple reasons" I suppose I should give more.

>> Another is

>> that the "handyman" seeing this in one location will figure he can

>> set it

>> up in his own location, sans the interlock (believing he will

>> "remember"

>> to open one before closing the other). And yet another is the fact

>> that

>> this arrangement, especially when tried on a subpanel (which might be

>> done

>> to limit the circuits powered by the generator), can result in a

>> ground loop

>> path for neutral currents (e.g. two or more points where the neutral,

>> which

>> is not switched, is bonded to the ground). If the generator has such

>> a bond, then you have a problem. If you might want to safely test

>> load the generator when utility power serves most of the house (e.g.

>> keep the two supplies and

>> two load sets isolated), you will need a generator neutral to ground

>> bond.

> I think you can also just not switch the neutral anywhere throughout the

> subpanel and rely on the main service panel neutral-ground bond.

> ISTR this is one way of tieing in a generator. Leave the generator

> ground-neutral unbonded and hard-wire the neutral throughout so it isn't

> switched.

> If you *do* switch the neutral in the transfer switch (i.e. use 3 pole

> switch) then you *must* bond the generator neutral and ground at the

> generator.

> Either way you only have neutral and ground connected together at one

> point (at a time).

> daestrom

>> There are some panels (seen them in a Schneider catalog) that have a

>> double

>> feed breaker arrangement where two molded case breakers can be placed

>> side by side. The framed sliding interlock would be easier that way

>> as it would not

>> have a contorted path.

>> Still, I much prefer the transfer switch, and prefer one that

>> includes switched neutral with the correct sequencing.

> Why do you think switching the neutral to be important?

> daestrom

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