Another whole-house (or less) Generator Question
#11
Re the recent threads about sizing, etc., I think I have a pretty good idea about the power needs.  I have a somewhat different problem and would like some opinions before taking the plunge.  Please bear with me, but here is the situation.  First, the water heater, cook stove, and backup furnace are on gas, so we can stay clean and not starve or freeze with very little power needed.  Currently have a 5500-watt portable Generac that actually fills the bill for most outages (fairly frequent thanks to all the trees around here growing right along the roads where the power lines run, plus the occasional person plowing into a power pole). Typical outages are 1-5 days, evenly divided between summer and winter.  The problems with the current solution are several, in addition to hassles with shutting down and refueling during extended outages.  The only place to park the portable generator is outside the garage which occupies half of the basement, and it is a 50-ft. or so run to where we want to power anything.  The main power breaker boxes, FIOS internet/TV gadgets, and telephone box are on the opposite side of the basement, another 40-ft. or so run.  Up the basement stairs is another 15 feet, then a 25-ft. wire to the fridge, a 25-ft. run to the internet router and main computer, and a few extension cords to various lights, TV, etc. We only run the fridge, fan in the furnace, or any other motors when needed - never the AC.  I rigged up a 10-AWG cable to carry 220 v. (two 120 V.) circuits into the house, but you can imagine the hassle to string out (and then rewinding) all that wire when the lights go out.

With all that said, my question has to do with a transfer switch to power a WHG panel.  When we built the house 31 years ago, I insisted on enough power for typical usage plus a workshop with several 220-v. machines.  We have TWO 200-amp. boxes side-by-side (the builder with a smirk said, "any more power and we would have to zone this as light industrial").  Of course there is no rhyme or reason to what circuits go where.  220 runs to the oven and dryer and two separate ones to the workshop, plus numerous "lights and receptacles" and what-not wired willy-nilly between the two boxes.  My question is, how much of a problem would it be to install a transfer switch/panel in this situation, given that I would need to access circuits (maybe 100-amp total) from both input panels? BTW, any permanent generator would be installed on the opposite side of the basement wall from the breaker boxes and next to the heat pump and gas meter.  And we could do without any of the 220 circuits short of an apocalypse.

Would appreciate any thoughts on this.

Gary  
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#12
Would consider getting a bid.

Still not enough info. 
Are there two separate meters, or a meter/main and the two 200 amp panels and any others (workshop and/or garage) actually subpanels?


With the two 200 amp panels adjacent, I would think it would be an easy change if one main and the 200 amp  panels are subs as they make meter sockets that incorporate a generator transfer to a automatic transfer switch.  
But, it is enough of a unique situation that more info is needed and a professional consultation would look to be beneficial.
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#13
The transfer switch would be between the meter and the house panel(s). So the comment above about how things are wired is a good one. If the meter is feeding both house panels separately, I suspect this would be a little more complex.
I started with absolutely nothing. Now, thanks to years of hard work, careful planning, and perseverance, I find I still have most of it left.
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#14
Quote:My question is, how much of a problem would it be to install a transfer switch/panel in this situation, given that I would need to access circuits (maybe 100-amp total) 


No problem with regard to wires coming from two panels.  It may be more work and take more wire  to fabricate the jumpers , but it’s not a “problem “

400 amp service is pretty common in my neighborhood, with 600a not being unusual. With regard to your layout , I assure you there is a rhyme and reason for how the panels were laid out.
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#15
Typically in a situation like yours, we would recommend installing a critical circuits panel and feed only it from the transfer switch. Move the circuits you want powered to that panel and install a gen set sized for that. You can include a few plug circuits in that set up.
Blackhat

Bad experiences come from poor decisions. So do good stories. 


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#16
(11-25-2021, 01:30 PM)blackhat Wrote: Typically in a situation like yours, we would recommend installing a critical circuits panel and feed only it from the transfer switch. Move the circuits you want powered to that panel and install a gen set sized for that. You can include a few plug circuits in that set up.

I will not be where I can look at the exact meter/panels layout for the next few days, but I know there is ONE meter, on the opposite side of the basement wall from the two panels and each panel has a master breaker switch.  There is no other subpanel - all circuits are fed directly from the main panels, most of the 120s are 20-amp., and most of the "lights/receptacles" wiring is 12 AWG.  I would need to look to see the wire gauge for the 220 v. wiring.

A "critical circuits" panel sounds like a good idea to explore with a prospective contractor.  All the wiring runs are compact with no obvious slack entering the panels - is this a further complication?
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#17
Sight unseen, it’s hard to say what will work best for you. What size genny, which circuits and where are they, how much room, budget…..  I’m just throwing another option on the table.
Blackhat

Bad experiences come from poor decisions. So do good stories. 


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#18
(11-25-2021, 01:30 PM)blackhat Wrote: Typically in a situation like yours, we would recommend installing a critical circuits panel and feed only it from the transfer switch. Move the circuits you want powered to that panel and install a gen set sized for that. You can include a few plug circuits in that set up.

This is the best solution when you only need certain circuits powered from a generator.  Power the gen panel from one of the two service panels, and move the critical circuits to the generator panel.  Move circuits that won’t be in the generator panel to the other service panel so the total load on each service panel remains about the same (unless there’s loads of headroom).  

If circuits need to be extended to reach the gen panel, use a splice box or use the service panel (it’s legal, but ask the sparky as that can be a local thing).  You’ll need to put filler plates in any open slots in either or both of the service panels (approved for those panels, which means made by the same company).

The gen panel will be fed with a 4-wire feeder for 120/240V (two hots, neutral, ground) from a 2-pole breaker in whichever service panel those circuits are powered from when on utility power.  That feeder, the gen panel, and the breaker powering it all needs to be large enough to run all the loads on the gen panel simultaneously since they’re ‘critical loads’, but remember that there are two poles so 60A of 120V load is divided between those two poles (30A each, plus 25%).  If the run to the generator inlet box is long, consider upsizing the feeder for voltage drop mitigation.
Tom

“This place smells like that odd combination of flop sweat, hopelessness, aaaand feet"
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#19
Quote:A "critical circuits" panel sounds like a good idea to explore with a prospective contractor.  All the wiring runs are compact with no obvious slack entering the panels - is this a further complication?


Again,   NO it’s not a problem. 

If it’s more complicated (it is btw) are you going to shelve the project ?

Whether it’s more complex , more work, harder , or easier shouldn’t be germain to your decision.  Choosing a contractor that knows what they are doing is the highest priority. Having a good report with them is key too.  If they can’t get you to communicate your needs and desires and tailor a solution to your budget then you’ll be back at square one again.  The guys I use are really good. But if you’re not in Atlanta or N.GA they’re worthless to you.  You gotta find someone in your area.
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#20
I'm not an electrician; I can only relate my experience with the installation of our Generac 22KW system with automated switching.

I have 400A service with two power panels side by side.  

The original configuration of the power panels was "scattershot", meaning, there was no rhyme/reason I could discern to the grouping of circuits as to where they sat in the panels.

A local electrician (family-owned electrical business doing mostly residential and farm work) is also a Generac dealer, so I used them for the work.

The electrician/Generac dealer told me that the standard automated switching system would work for one panel; running backup power to both panels would be more complex and expensive.  

I sat down and mapped which circuits were required on backup power, which would be "nice" on backup power, and which were not needed on backup power.  I provided a "map" of those circuits to the electrician, and he "moved" them to the new placement in the panels.  The way he "moved" the breakers between the panels surprised me.  I thought it would require pulling an individual power cable out of either the right or left panel and moving it to the other panel in the new placement.  Not so; instead, the electrician "extended" each individual circuit inside the original power panel, and using a 3" (?) conduit "path" pulled the extended wire from one panel to the other.

The new backup power system can provide power to all that is needed; only a few outlets/lights in guest rooms upstairs and a few 220V outlets in LOML's craft room are not powered when using the backup generator.  I even have backup power to the shop building and our new machine shed.

I thought it odd that the circuits were extended in the manner that the electrician did the work.  I asked my regular electrician about this method, and he told me that's the way he would have done it since the original wiring configuration would not have provided enough slack to move circuits between panels.

Anyway, that's my experience....
Ray
(formerly "WxMan")
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