Automatic transfer switches: general questions

[Mr. Serious]

I've been putting this off far too long, because it seems complicated. I told a customer that I could quote a transfer switch for them, but I haven't ever bought or installed one before, so I have some very general questions.

I believe I am looking for a 200A service-rated outdoor transfer switch. NEMA 3R rating is fine. This will be mounted on the outside north wall of a house in far south Tulsa County, Oklahoma. The meter can will be on the outside of the wall too, and the main panel is already mounted on the inside of the wall

1. Do neutrals and grounds need to be separated within the main panel, and the bonding be done only within the transfer switch? I originally intended to do so, but the journeyman on the job didn't see the separate ground bar I had included and he wired the neutrals and grounds all together in the panel. It would be difficult to change now.

2. Searching for such a transfer switch, the first one I found was the ASCO Series 185SE, model 1AUSA2200F4M. I first looked at it in November and found a listed price of $1700, and I believe that's up to about $1800 now on the one vendor I found with a price listed. However, today I just found the Generac model RXSW200A3 listed for about $800 from three different vendors. Is the ASCO better quality, worth an extra $1000? Perhaps if I ask for a quote it would be a little cheaper than listed.

3. Also listed with the ASCO transfer switch was an acccessory, a heater that goes inside the box for cold weather. How necessary is it? I expect with the north-facing wall, this unit will be exposed to the full extent of the lowest temperatures we get around here, usually -10°F or greater, but we have had two recent winters with a few hours to a day of -20°F temperatures.

4. Recommend any other accessories to have, or features to look for.

 

[augie47]

I'll leave 2-4 to the generator folks but as to question 1, the neutrals and equipment grounds must be separated after the service rated transfer switch, MBJs removed from interior panels, and GECs terminated at the transfer switch.

 

[Hv&Lv]

This is simply my $.02 worth of experience.
I have the generac transfer switch you are showing. I believe it’s the normal 200A service rated switch included with the generac generator/switch/pad kit.

Mine has done fine. Yes, I separated all my neutrals and grounds in my breaker panel 2’ away from the switch.

The only issue I have found in my line of work is the actual transfer switch doesn’t actually switch over all the time.
I get a bunch of calls after a large outage event over our utility system regarding generators that won’t switch over now that the power is back on.
I tell them to manually turn the generator off. Once it’s off it will switch over. From there they need to call an electrician but none have ever returned my call to tell me exactly what was wrong.
Not a requirement at our utility, I’m just curious.

The switch controller is about $125.
The actual transfer switch is about $500

I’m really hoping mine switches over every time for a few years anyway..

 

[Birken Vogt]

I've been putting this off far too long, because it seems complicated. I told a customer that I could quote a transfer switch for them, but I haven't ever bought or installed one before, so I have some very general questions.

I believe I am looking for a 200A service-rated outdoor transfer switch. NEMA 3R rating is fine. This will be mounted on the outside north wall of a house in far south Tulsa County, Oklahoma. The meter can will be on the outside of the wall too, and the main panel is already mounted on the inside of the wall

1. Do neutrals and grounds need to be separated within the main panel, and the bonding be done only within the transfer switch? I originally intended to do so, but the journeyman on the job didn't see the separate ground bar I had included and he wired the neutrals and grounds all together in the panel. It would be difficult to change now.

That depends. Are you running from an isolated meter can, to the transfer switch as first point of disconnect, to the panel as a subpanel? (A sketch would be nice.)

If so, then the GES, N-G bond, etc. all need to be done in the transfer switch, and the panel done as any other downstream subpanel, all separate.

2. Searching for such a transfer switch, the first one I found was the ASCO Series 185SE, model 1AUSA2200F4M. I first looked at it in November and found a listed price of $1700, and I believe that's up to about $1800 now on the one vendor I found with a price listed. However, today I just found the Generac model RXSW200A3 listed for about $800 from three different vendors. Is the ASCO better quality, worth an extra $1000? Perhaps if I ask for a quote it would be a little cheaper than listed.

The RXSW200A3 works only with specific Generacs and nothing else. Is that the generator you have? If you use an ASCO 185, a Generac would need a small reconfiguration to work with it. Other more commercial generators would work with no mods. Some bottom of the barrel might not work at all.

3. Also listed with the ASCO transfer switch was an acccessory, a heater that goes inside the box for cold weather. How necessary is it? I expect with the north-facing wall, this unit will be exposed to the full extent of the lowest temperatures we get around here, usually -10°F or greater, but we have had two recent winters with a few hours to a day of -20°F temperatures.

I can't speak to that, I live in Ca.

4. Recommend any other accessories to have, or features to look for.

Keep things simple and standard. Features are for suckers.