2W panel?

[ne0031]

I was searching for a 2W/120 panel and found this post from more than 10 years ago - https://forums.mikeholt.com/threads/120v-single-phase-panelboard.108029/

The AHJ follows 2023 NEC and this is a residential install.

The installation has a regular 200A service and a 240/120 30A manual transfer for generator. The resident wants to remove the transfer switch and install a multi-input solar device (utility, generator, PV, battery). Due to limitations with split phase output capacities, he wants to use a 240 output unit with a step down transformer for 120 loads. After briefly considering it, I agree that the use of a step down presents advantages in the availability/selection of the solar units. Expanding beyond this particular question, I see the same advantage if he simply wanted to more efficiently use his generator (no solar) by not having to attempt to balance loads across legs - I've done this myself.

Thus I started searching for a single column panel. Finding that a suitable product from Siemens was discontinued (a generator panel) several years ago, the only other products I've found are industrial focused units.

I spoke with the local inspector regarding using a regular 3W panel and blanking one side as mentioned or jumping L1 to L2 and profusely labeling that the panel was for 120 loads only and he rejected both.

It seems that without a 2 wire panel, this may be a goose chase. Has anyone run into this?

 

[don_resqcapt19]

I see no reason why you can't tap the one hot to jumper it to the other side. Not sure what code rule would prohibit that. It is specifically permitted by 710.15(C) for stand alone systems.

 

[ne0031]

I think his issue was that it is grid tied, though not net metered.

 

[brycenesbitt]

Use some of these in a DIN rail enclosure. Just hit up a supplier for industrial panelboards, and get the UL489 versions.

Wire in wire out.

 

[Birken Vogt]

I don't see how the inspector can reject it. He needs to cite a code section.

It was done all the time around here also. Off grid installations of course, but also there were some Y2K systems that had only 120 volt battery inverters, they would get a critical loads subpanel that was all 120 with both sides jumped together like this. Typically done by mid stripping a #6 and passing it through one lug and terminating in the other one.

 

[WD40]

There is a mid-rise apartment building here that has all the studio units on 120V panels, they were as you mention a single buss panel. When I have replaced them use a small 8 circuit panel and jumper the phases simple as that. FYI you can even order a 60A single pole breaker from Siemens.

 

[brycenesbitt]

Here's an enclosure for up to 12 single pole breakers:


EK012 - 542-512
It's not available in flush mount though, you'd have to put some trim around it yourself.

 

[ne0031]

An update. The AHJ could/would not cite a reference on jumping a regular 3W panel. He didn't seem to be on a power trip, however, he said he wouldn't grant a permit for a jumped panel. The resident is reconsidering his solar options at this time.

Thanks everyone for your comments.

 

[jim dungar]

Here's an enclosure for up to 12 single pole breakers:
View attachment 2581080

EK012 - 542-512
It's not available in flush mount though, you'd have to put some trim around it yourself.

It also probably isn't UL Listed. Not all PVC enclosures pass US smoke requirements.

 

[tortuga]

An update. The AHJ could/would not cite a reference on jumping a regular 3W panel.

I'd pick a panel, read the sticker on the panel, check with Eaton or Siemens there is nothing on the sticker / UL listing other wise, and kindly make a appeal.
You could also of course also use a 240: 120/120 single phase to split phase transformer.
There are still 120V services in real rural places here (I can think of two I know of other than gate or lighting services). Or entirely off grid cabins as don mentioned its in the code.
I think the rural electric COOP's used to have a lower rate tier for 60A 120V.

 

[brycenesbitt]

It also probably isn't UL Listed. Not all PVC enclosures pass US smoke requirements.

The UL control number is E254144 as BGUZ
Guenther Spelsberg GmbH + Co. KG

There's a separate variant for Canada, because, well, you know.

At 26.5 deaths per million population, the U.S. rate of fire deaths was over five times that of Switzerland, the nation with the lowest rate of all the countries considered – only 5.2 deaths per million population.

"
This has held true for both fire deaths and dollar-loss rates.
The causes of the United States prominent standing in this
area are not entirely clear and have been the subject of
debate for some time. To compound the issue, the United
States is comparatively safety conscious and one of the most
technologically-advanced nations in the world. To have such
high fire death rates is perplexing for a country that ranks
so highly in those two areas. "
The differences could be due to a number of factors, including fire
prevention practices and education, building practices and
regulations, differences in lifestyle, and cultural attitudes.
For example, Japan has an acute problem with incendiary suicide, which pushes up the number of fire deaths
considerably.