# When to Install Automatic Transfer Switch



## NolaTigaBait (Oct 19, 2008)

Yeah, It's easier IMO.


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## Roger123 (Sep 23, 2007)

I think the best procedure is to install a generator ready load center now. Then there will be only one panel and the transfer switch can simply be installed in the load center when the customer is ready.


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## wildleg (Apr 12, 2009)

It's a better install to put the generator panel/transfer switch in now.


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## 480sparky (Sep 20, 2007)

It's a lot easier for auto manufacturers to install things like steering columns and axles and windshields at the factory than it is for the dealers to install them at their lots.

Install it now, and when it comes time to install the generator, the power can stay on during that time.


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## Magnettica (Jan 23, 2007)

majohn said:


> For a new build the client is considering a 10 kW Generac Generator....but is not ready to install it right now...but will at a future date. The electrician is insisting it's easier and more efficient to wire up the transfer switch at the time he is wiring up the main panel (like now). I have someone else telling me there's no advantage to wiring it now as opposed to later when the generator is actually installed. I'd like to hear from others about this.... any opinions? Thanks. John


My experience is to do what the HO wants you to do. We know that now is the time to install it because it's easier for us to wire it now rather than later. But as an electrical contractor it's not about what we want to do, it's what the customer wants us to do. :thumbsup:


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## JayH (Nov 13, 2009)

Magnettica said:


> But as an electrical contractor it's not about what we want to do, it's what the customer wants us to do. :thumbsup:


As long as their pockets are deep enough, they can have whatever added cost they want.


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## Magnettica (Jan 23, 2007)

JayH said:


> As long as their pockets are deep enough, they can have whatever added cost they want.


Exactly. :thumbsup:


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## Amish Electrician (Jan 2, 2010)

Generators seem to cause all manner of confusion, so for the benefit of those who might someday see this thread, let me draw a few pictures.

Normal Service: PoC0 --> Meter --> Disconnect --> Panel

ANY SDS, including generators:

PoCo -->Meter --> {Interconnection point} <-- Second power source
:
:
V
Panel

When you have a generator, the transfer switch contains your disconnecting means as well as being a 'transfer' switch. In a very real sense, the transfer switch IS your service disconnect. This is especially true with automatic transfer switches.

As you can see, the transfer switch goes between the panel and the meter. There's simply no way to put this in later, without having to take everything apart. At least put the cabinet in; you can cut & connect the wires to the guts later.

Now, I will qualify my statements here very slightly. For very small (dare I say 'portable' ) generator installs, where the panel is surface mounted, it IS possible to add a 6-circuit manual transfer switch later, without disrupting much. For anything else, you'd have to kill power to the entire panel and probably remove it as well.


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## brian john (Mar 11, 2007)

:
:
V
Panel



> When you have a generator, the transfer switch contains your disconnecting means as well as being a 'transfer' switch. In a very real sense, the transfer switch IS your service disconnect. This is especially true with automatic transfer switches.


not necessarily actually VERY SELDOM and I was a service rep for ASCO for 20 years.



> As you can see, the transfer switch goes between the panel and the meter. There's simply no way to put this in later, without having to take everything apart. At least put the cabinet in; you can cut & connect the wires to the guts later.


not necessarily actually VERY SELDOM and I was a service rep for ASCO for 20 years.




> Now, I will qualify my statements here very slightly. For very small (dare I say 'portable' ) generator installs, where the panel is surface mounted, it IS possible to add a 6-circuit manual transfer switch later, without disrupting much. For anything else, you'd have to kill power to the entire panel and probably remove it as well.


Time to write a paper on ATS's???????

Because with the exception of some resisdences this is in my opinion VERY WRONG.


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## Amish Electrician (Jan 2, 2010)

Well, Brian, I appreciate your perspective.

I've never installed a generator smaller than 100 KW, so my generator comments are often 'over design' for small residential systems.

I've yet to see a system - including those using ASCO equipment - wher the transfer switch wasn't the ONLY single point where you could disconnect the facility from ALL sources of power. Sure, you could flip the disconnect at the PoCo service, then run across the parking lot or around the building to kill the generator. Or, you could go to the nearby switchgear and flip all the buckets off.

Now, whether the transfer switch in the middle position qualifies as a 'service' disconnect is another discussion.

Let's look at one installation:









That big green box is the transfer switch. The panel to the right used to be where the transfer switch now rests. Had those cabinets not been mounted on the surface, it would have been nearly impossible to later add the switch.

The panel lacks provision for a main breaker. Shut off the switch under the meter, and all you'll do is start up the generator.

The arrangement you just saw replaced this:









A portable generator was set up outside, and supplied power to the manual transfer switch you see mounted next to the panel. This allowed them to power six circuits. For the manual switch, the "PoCo" feed came from the breakers in the panel, and the branch circuits were routed to the transfer switch.

Naturally, I'd be delighted to read that paper if you ever write it. IMO, the transfer arrangement, and the exercising regime, are far more important that the specific generator chosen.


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## brian john (Mar 11, 2007)

The big green box is an Onan ATS, I service those also as well as Zenith, Lakeshore and Generac.

Typical installation that I/we see is utility service to main service disconnect (circuit breaker or fuse) then ATS; with Normal in the ATS being the utility, Emergency in the ATS being the second source (typically a generator) and Load tied to the distribution equipment.


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## smitty1358 (Dec 5, 2009)

*Ats*

I would have piped that job another way. To busy not very clean.


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## drsparky (Nov 13, 2008)

Why don't you listen to your electrician?


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## smitty1358 (Dec 5, 2009)

*Ats*

The junk on the inside is even worse. Bad craftsmanship. Just sayin:thumbdown:


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## Amish Electrician (Jan 2, 2010)

Thank you, Smitty. 90% of that pipe was already in place; I had to make lemonade from the lemons they gave me. Indeed, in that picture only one pipe - the one from the panel with the 90 in it - is completely new.


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## smitty1358 (Dec 5, 2009)

*Ats*

Why dont you listen........seems I heard that be........wait, I might have said it!


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## smitty1358 (Dec 5, 2009)

*Ats*

Why did you cross those other pipes with that 90. Could you have not penetrated that bldg. where you turned your 90?


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## B4T (Feb 10, 2009)

I would try to sell them a whole house transfer switch.. much better idea and the transfer switch goes outside the house.

Here is a job i did last year with a (20) KW generator controlling (2) 200a 

services.


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## user4818 (Jan 15, 2009)

Black4Truck said:


> I would try to sell them a whole house transfer switch.. much better idea and the transfer switch goes outside the house.
> 
> Here is a job i did last year with a (20) KW generator controlling (2) 200a
> 
> services.


Wow. Where do you even begin? Why is the service on the right a complete abortion? SEU sleeved in EMT? No LB on the bottom? Working space violation with the condensing unit? :blink:


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## B4T (Feb 10, 2009)

Peter D said:


> Wow. Where do you even begin? Why is the service on the right a complete abortion? SEU sleeved in EMT? No LB on the bottom? Working space violation with the condensing unit? :blink:


That service was done about (20) years ago.

The POCO wants the SEC protected from that chain saw guy who attacks exposed romex. :icon_lol:

Using a sill plate is SOP here for SEU going into basement. 

The AC unit was not an issue :thumbsup:

The lugs on the right MP were rusted, so I had to change it


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## JayH (Nov 13, 2009)

Black4Truck said:


> The AC unit was not an issue :thumbsup:


Doesn't look like 3' clear to me. Was there an inspection?

What's all that jizz all over the fittings?

Where is the strap within 3' of the box on the service on the right?

You have some illicit pics of the inspector and a goat or something?


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## user4818 (Jan 15, 2009)

Black4Truck said:


> The POCO wants the SEC protected from that chain saw guy who attacks exposed romex. :icon_lol:


Oh, right. :laughing: 



> Using a sill plate is SOP here for SEU going into basement.


Same here, but to make it match the other service why not just use an LB? 

Otherwise it's among the finest abortions I have ever seen. :thumbsup:


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## John (Jan 22, 2007)

Amish Electrician said:


> Generators seem to cause all manner of confusion, so for the benefit of those who might someday see this thread, let me draw a few pictures.
> 
> Normal Service: PoC0 --> Meter --> Disconnect --> Panel
> 
> ...



Better picture.:thumbsup:
View attachment 2404


The state POCOs require this setup or will not turn the power on.:no: 

Disconnecting means can be inserted in different places but the wiring sequence has to be the same.


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## B4T (Feb 10, 2009)

JayH said:


> Doesn't look like 3' clear to me. Was there an inspection?
> 
> What's all that jizz all over the fittings?
> 
> ...


That is silcone caulking and the job was inspected. 

The HO saw a TOH show about winterizing 

I had to fix the CATV wires yet and that is when I put the straps on.

No goat or sheep pics


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## B4T (Feb 10, 2009)

Peter D said:


> Oh, right. :laughing:
> 
> 
> 
> ...


I asked about the LB.. (not doing it for free) but changing the MP killed the budget.

I could not just put an LB on there without making a 2" hole for a 3" piece of PVC through the rim joist... which means taking out the SEU first.


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## brian john (Mar 11, 2007)

Peter D said:


> Wow. Where do you even begin? Why is the service on the right a complete abortion? SEU sleeved in EMT? No LB on the bottom? Working space violation with the condensing unit? :blink:


You ever notice the only pictures I post are of blow ups. I never post pictures of completed jobs, I could not take Peter's criticism, it would break me.


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## leland (Dec 28, 2007)

Peter D said:


> Wow. Where do you even begin? Why is the service on the right a complete abortion? SEU sleeved in EMT? No LB on the bottom? Working space violation with the condensing unit? :blink:



Man! your a tough sell!!
That Aint the worst you've seen!! 
The clearance.Bad angle on the camera. Live parts you got the clearance.
Looks good with what you have to work with. Apparently the AHJ agreed.:thumbsup:


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## leland (Dec 28, 2007)

brian john said:


> You ever notice the only pictures I post are of blow ups. I never post pictures of completed jobs, I could not take Peter's criticism, it would break me.




:yes::yes:


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## JayH (Nov 13, 2009)

brian john said:


> You ever notice the only pictures I post are of blow ups. I never post pictures of completed jobs, I could not take Peter's criticism, it would break me.


You gotta admit he left himself wide open with those pics!

I only hope it doesn't end up in another poll.


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## B4T (Feb 10, 2009)

brian john said:


> You ever notice the only pictures I post are of blow ups. I never post pictures of completed jobs, I could not take Peter's criticism, it would break me.


 
YES.. he is tuff sell :yes::yes:


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## John (Jan 22, 2007)

Peter D said:


> Oh, right. :laughing:
> 
> 
> 
> ...


I see the Rat Patrol has arrived.:thumbsup::jester: 

View attachment 2405


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## B4T (Feb 10, 2009)

leland said:


> Apparently the AHJ agreed.:thumbsup:


Thank-you very much.. that is *ALL* that matters :thumbsup:


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## B4T (Feb 10, 2009)

JayH said:


> You gotta admit he left himself wide open with those pics!
> 
> I only hope it doesn't end up in another poll.


I knew that as I posted them 

I really don't have a problem with any comments or question.. good or bad :thumbsup:

I like them polls.. gives us something to beat up.


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## paul d. (Jul 13, 2008)

you know, i dont think the OP is an electrician. probably a HO looking for some free advice. :no:


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## Amish Electrician (Jan 2, 2010)

No, Smitty, the area inside where the pipe might have gone was occupied by the heating plant, and other mechanicals. That inside panel ... all I did was get rid of the manual transfer switch. Not my bowl of spaghetti.

John ... nice art in the link! OTOH ... what you drew in your post sure looks like the genny power gets run through the meter. I bet the PoCo likes that!


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## drsparky (Nov 13, 2008)

paul d. said:


> you know, i dont think the OP is an electrician. probably a HO looking for some free advice. :no:


That's what I think, his profile say he is a building.


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## user4818 (Jan 15, 2009)

brian john said:


> You ever notice the only pictures I post are of blow ups. I never post pictures of completed jobs, I could not take Peter's criticism, it would break me.


I wouldn't want to see you harm yourself because of my criticism, so I promise if you post something I'll go easy on you. :thumbsup:



Black4Truck said:


> YES.. he is tuff sell :yes::yes:


Obviously I'm giving you a hard time for fun, but the sleeved SEU cable and slicone and sill plate thing looks a bit hackish. I guess if your poco doesn't allow exposed SEU you're stuck doing that. 



John said:


> I see the Rat Patrol has arrived.


Of course. :jester:




Black4Truck said:


> Thank-you very much.. that is *ALL* that matters


That is a pretty slippery slope, don't you think? Just because the AHJ passed an installation doesn't make it compliant. But we've had that discussion before.


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## DipsyDoodleDandy (Dec 21, 2009)

*Last summer*

here is something we hooked up last summer. Anything wrong that you can see?


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## B4T (Feb 10, 2009)

Peter D said:


> That is a pretty slippery slope, don't you think? Just because the AHJ passed an installation doesn't make it compliant. But we've had that discussion before.


I'm out to make money, not change the world as it is. 

If I said the AC compressor has to be moved, the people would of found someone who said it was fine the way it is.

There is not a hazard there and I sleep just fine :thumbsup:


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## user4818 (Jan 15, 2009)

Black4Truck said:


> I'm out to make money, not change the world as it is.
> 
> If I said the AC compressor has to be moved, the people would of found someone who said it was fine the way it is.
> 
> There is not a hazard there and I sleep just fine :thumbsup:


:yawn:


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## John (Jan 22, 2007)

Amish Electrician said:


> No, Smitty, the area inside where the pipe might have gone was occupied by the heating plant, and other mechanicals. That inside panel ... all I did was get rid of the manual transfer switch. Not my bowl of spaghetti.
> 
> John ... nice art in the link! OTOH ... what you drew in your post sure looks like the genny power gets run through the meter. I bet the PoCo likes that!


I did not draw the picture. The picture/document is issued by the POCOs....Because they want it this way. :yes:

The gen power does not back feed the meter due to the two pole double throw manual switch or automatic transfer switch. Look closely at the drawing


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## Magnettica (Jan 23, 2007)

DipsyDoodleDandy said:


> here is something we hooked up last summer. Anything wrong that you can see?


I was going to say no coffee. But upon further review I see you have that covered.


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## drsparky (Nov 13, 2008)

DipsyDoodleDandy said:


> here is something we hooked up last summer. Anything wrong that you can see?


How close is your parallel conductor length?


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## smitty1358 (Dec 5, 2009)

*Ats*

To much phasing tape, cant tell if your safety glasses are on, coffee cup to close to the edge. Looks good.


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## DipsyDoodleDandy (Dec 21, 2009)

*....*

I think it was less than 5" off. I sent the better guys off the next day to do this one.


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## Magnettica (Jan 23, 2007)

What if I have an existing service, would I still need to install ATS between the meter and main disconnect? Or could I install an emergency panel next to the main panel and install the ATS between those two? It is not a whole house generator.


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## B4T (Feb 10, 2009)

Peter D said:


> :yawn:[/quote
> 
> [URL="http://www.mysmiley.net/free-mad-smileys.php"][/URL]


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## B4T (Feb 10, 2009)

Magnettica said:


> What if I have an existing service, would I still need to install ATS between the meter and main disconnect? Or could I install an emergency panel next to the main panel and install the ATS between those two? It is not a whole house generator.


The ATS can go anywhere.. those are Service Rated for this installation.

I could of just put a 100a panel dedicated to generator and transfered over the circuits,

Space is always a problem and installing the ATS outside fixes most issues

I would of used a combo ATS and load center inside the house.


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## DipsyDoodleDandy (Dec 21, 2009)

*....*

Ever installed a 350kva transfer switch or above black?


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## B4T (Feb 10, 2009)

DipsyDoodleDandy said:


> Ever installed a 350kva transfer switch or above black?


The biggest I ever did so far was a 200A ATS


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## Magnettica (Jan 23, 2007)

Black4Truck said:


> The biggest I ever did so far was a 200A ATS


What was the size of the generator?


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## B4T (Feb 10, 2009)

Magnettica said:


> What was the size of the generator?


I have installed 16, 18, and 20 KW generators on 200a ATS.


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## DipsyDoodleDandy (Dec 21, 2009)

*?*

Not sure. He said he needed 350,000W to keep 6 Giant Meat Coolers working during an outage. I said do they all have to stay on at once..and he said yes. He wasn't willing to go with a load managment system at first. Once I gave him vague numbers of 350kw Generators he started to double think. He said he was just going to go out and rent one in the middle of the night to hook up when needed????


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## B4T (Feb 10, 2009)

Magnettica said:


> What was the size of the generator?


I could of installed a 6KW generator on a 200a ATS.

The generator has a 30A main breaker that would trip if load is too much.


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## active1 (Dec 29, 2009)

Black Truck - You have ground bars and some maybe #12 EG's but nothing is bonding the transfer switch and only pvc is used (not counting the sleve). The transfer switch is the service disconect. After that going to the panels it a feeder. You need an insulated neutral and EG in you case. See 338.10(B).

You phased the red but then crossed em up it in the right transfer sw.


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## user4818 (Jan 15, 2009)

active1 said:


> You phased the red but then crossed em up it in the right transfer sw.


"Phase" is irrelevant on a 120/240 volt service.


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## active1 (Dec 29, 2009)

Peter D said:


> "Phase" is irrelevant on a 120/240 volt service.


Exactly. So why tape em? And then change it up.


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## user4818 (Jan 15, 2009)

active1 said:


> Exactly. So why tape em? And then change it up.


Good question. :blink:


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## Magnettica (Jan 23, 2007)

I know why.... in case there's ever an issue with one of the conductors you'll know which one needs to be changed. I would prefer to use blue though because the POCO guys might freak out when they see red and think they've come across the first ever single phase high leg service.


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## smitty1358 (Dec 5, 2009)

*Ats*

That is a very good post Mr. Magnettica, all ways phase, label, ID your circuits, feeders. Fail to plan, plan to fail!


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## B4T (Feb 10, 2009)

Magnettica said:


> I know why.... in case there's ever an issue with one of the conductors you'll know which one needs to be changed. I would prefer to use blue though because the POCO guys might freak out when they see red and think they've come across the first ever single phase high leg service.


That is correct about marking the conductors. :thumbsup:

The SEU comes with black and red, if I started using blue tape this thread would go to 200 posts by the morning. :laughing:


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## user4818 (Jan 15, 2009)

Black4Truck said:


> The SEU comes with black and red, if I started using blue tape this thread would go to 200 posts by the morning. :laughing:


Highly unlikely. :yawn:


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## brian john (Mar 11, 2007)

In lieu of utilizing L1, L2 in a single phase 120/240 VAC service by default it has been my experience most electricians to simplify terminology or just out of a total misunderstanding of the distribution at hand utilize the term phase A and phase B. While technically incorrect it works.


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## active1 (Dec 29, 2009)

To me it looks like the generator control wiring is powered off 2 different services. I wonder how that would affect the utility bills. The utility 1 & 2 control terminals should only be connected to one of the transfer switches. The other terminals 23 & 194 should be connected to both transfer switches. If this is the case I guess it's a good thing the line side was phased or you would have blown the ATS fuses.


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## Mountain Electrician (Jan 22, 2007)

brian john said:


> In lieu of utilizing L1, L2 in a single phase 120/240 VAC service by default it has been my experience most electricians to simplify terminology or just out of a total misunderstanding of the distribution at hand utilize the term phase A and phase B. While technically incorrect it works.



You're right. I do it all the time myself.


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