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Generator Transfer Switch: Combining Multiple House Circuits on One Switch Circuit? - Page 3

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Posted by (PeteCresswell) on December 8, 2012, 10:27 pm
 
Per Mr Clarke:

Maybe in somebody's dreams.

I'll Google it.

Thanks.
--
Pete Cresswell

Posted by mike on December 7, 2012, 3:24 am
 
On 12/6/2012 6:19 PM, (PeteCresswell) wrote:

I'm no expert.  I know about how electrons behave.
I don't know a lot about the details of the electrical code.

The electrical code is like a lawbook.  Evolved over the ages to
codify acceptable behavior.  But the devil is in the details.
You may do something that you think is perfectly reasonable
and still be in violation.  That's why we have inspectors.
And they don't always agree.

What follows is based on logic and conjecture.  The electrical
inspector is the one you need to ask.

Assume for the sake of argument that a 15A breaker actually tripped
at 15.00 AMPS.  Assume you have #14 wire in the circuit.
If you load any point on any downstream line to 15.1A, the breaker
should trip.  There is no way you can overheat any part of the
wire as long as the breaker is functional.

If you have a #14 wire from the input side of the 15A breaker to the
output side of a 20A breaker, you could logically argue that
the wire can never experience more than 15A because of the second
15A breaker.
And the inspector might agree with your logic as he wrote
"fail" on the inspection report. ;-(

I made all that up.  Ask the inspector or a licensed electrician.

Just flashed on another issue.
If you have 240VAC service, your 120VAC loads will be split with an
attempt to balance the load on the two halves.
If you have a 120VAC generator, the switch will have to combine
circuits from two phases onto a single phase generator.
That might make for some interesting transients when the power
comes back on.

Posted by (PeteCresswell) on December 7, 2012, 11:28 pm
 Per mike:

Waited for my better half to go shopping today and fooled around
with the gennie/xfer switch for a few hours.

It seems to tolerate cutting/resuming utility power with no
problems that I can see.   Delicate stuff like the TV, LAN
server, computer are on UPS', so maybe that helps.

Once I figure out how to have come control over which circuits
get shed in what order when there's too much for the gennie, I
think I'll be a happy camper with this thing - albeit critical of
the manuals.... but then I'm one of those compulsive fault
finders and I can write a single-spaced 8x10 page of negative
rants on almost any product I buy.... -)
--
Pete Cresswell

Posted by mike on December 7, 2012, 11:48 pm
 On 12/7/2012 3:28 PM, (PeteCresswell) wrote:

The interesting thing about the "shedding" section of the manual
was that the graph has no dimensions.
Shedding works well when the incremental loads are insufficient to
stall the system, or when you sit between the event that initiates
the function and the function itself so you can shed loads BEFORE
adding loads and sensing overload.

When you have a 2kW generator and a 1500W microwave and a 1300W bathroom
heater and a 700W furnace air handler and...and...and...
You might want minimum on/off times for the furnace and fridge.
Starting the microwave might leave you with nothing that can be shut
down and a stalled generator.
That kinda puts you in the position to manually shed loads before
you start the new one.

It wasn't much more expensive than a manual switch, so, no big deal,
but I'm not optimistic that it's all the marketing hype would lead
you to believe.
It'd be more interesting if you could install it before the wiring
went in so you could have direct access to the loads you want to
focus on.

I have this vision of the stairwell lights going out just as
you step off the top platform with a heavy box of junk.
"Honey, I'm microwaving some coffee...want some?"
;-)

Posted by (PeteCresswell) on December 8, 2012, 2:12 pm
 Per mike:

I had a similar vision of The Better Half chopping celery in the
kitchen and Yours Truly stupidly turning on the bathroom lights
where a heater was plugged in.

I discovered a circuit parm called "Delayable" that *sounds* like
it exempts the circuit from being shed if set to False.  

"Delayable Circuits   The factory default setting is NO.  Setting
a circuit to YES, enables the UTS to run ALM for the individual
circuit selected."

Next time I have the house to myself, I'm going to try some more
stress testing and see what happens when I do various things.

I'm thinking a 1,500 watt electric heater or two will be useful
tools in that regard.  Also, I have found that just a toaster
takes almost 1,000 watts.
--
Pete Cresswell

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