Manual Transfer Alternative for Optional Standby Systems?

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Steve’s Electric

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Hello, this is my first post. I would like some opinions on this method of transferring over to an Optional Standby Panel that is fed from a portable generator. I saw this in a how-to book written back in the 1970’s. The author, an electrician, said he had done this all across the Florida Panhandle which is a region prone to lighting strikes and power outages. I don’t have the book anymore but I have tried to it describe it as best as I can remember. And I am trying to make sure it complies with the NEC. At first glance it looks like a very dangerous back-feed installation by a homeowner who thought he was an electrician.
But in my opinion it may solve a number of issues. The Standby Panel is a standard 100 Amp main lug only sub panel which is mounted next to the Service Panel.
Because of this method the floating neutral block in the Standby Panel (sub panel) will be completely isolated from the Service Panel’s bonded neutral during Standby mode and this allows the neutral in the portable generator to be bonded to the generator frame (which I think most of them are) and makes the generator a Separately Derived System.
The Standby panel has a 4 wire 50 Amp Range Cord connected to it’s main lugs, floating neutral block and bonded ground block. This cord is plugged back and forth between a receptacle fed from the Service panel and a receptacle which is fed from the generator. Normally this change would be done by switches or by a relay.
A #4 solid copper wire could bond the Standby Panel to the Service Equipment Panel which will keep the Equipment Grounding System intact. Or this could be done with a 2” steel nipple that is used to take the hots and neutrals spliced from selected circuits in the Service Panel and taken over to breakers in the Standby Panel.The only thing in common between the 2 panels during the Standby mode is the equipment grounding. Grounding conductors related to circuits taken from the Service Panel would remain in the Service Panel.
The receptacles are 2 50 Amp NEMA 14-50R within reach of the range cord from the Standby panel. One is fed from a 50 Amp breaker in the Service Panel for normal use. The other is from the generator and is fed through the the wall from outdoors from a 30 Amp L14-30 twist-lock inlet in a weatherproof housing that the generator cord plugs into.
Instead of going to the main lugs to feed the Standby Panel the range cord could feed the Standby Panel through a 50 Amp 2 pole breaker with a “hold down” clip.
The range cord hangs out of the bottom of the Standby Panel and is plugged back and forth between the 2 50Amp receptacles.
The generator has over current protection built in. The twist-lock inlet outdoors is the disconnect. The generator does not need a ground rod.
Cords are allowed for “frequent interchange”. And an example can be mentioned that Mobil Homes are fed with 50 Amp cords.
Maybe some of you are already familiar with this idea.
Please give me some opinions. This seems like it could be accomplished with one trip to the home improvement store if they had the proper size twist lock inlet for your generator and the cord. Most often 20 or 30 Amp. I tried to post a drawing, it didn’t seem to work.
 
I don't know if the code would allow a permanent subpanel to be cord and plug connected and I hate the idea of it.

Since as an installer you can't ulitmately control whether the user's generator has a bonded neutral, I think it's better to accept the risk of objectionable current on the EGC. IMO that's a less dangerous scenario than the one where you set up a separately derived system and the user plugs in a generator whose neutral isn't bonded.

If we're being serious about this, let's also encourage everyone to stop ignoring the signage requirement in 702.7(C). You're supposed to put a sign to tell the user of the inlet whether to have a bonded neutral or not. I've never seen this followed.
 
Sounds like the Green Acres method of power switching. I put the required signage on my inlet 3 years ago. It is looking quite faded now (it gets a lot of morning sun), and in a few more years that decal will probbly be totally gone.

Inspecror did not care about the inlet or sign, and didnt even look at it. I dont think he had seen the warning sign on the main panel either about removing the ground when under generator power.
 
jaggedben said:
If we're being serious about this, let's also encourage everyone to stop ignoring the signage requirement in 702.7(C). You're supposed to put a sign to tell the user of the inlet whether to have a bonded neutral or not. I've never seen this followed.
Click to expand...

All of mine gets the sign. 👍 And I get a compliment from the inspector for putting up signage and knowing what torque values were required, and even offering to pull out the torque wrench and demonstrate. 👍


Do I get a gold star now?
 
Description sounds as if there are several code violations related to article 400. Article 400.12 prohibits the usage of Cords as substitute for permanent wiring and from passing thru a wall or doors/windows.
 
I made a photo of a drawing but can’t figure out how to post it. The cord doesn’t go through a wall or run through a doorway or window.
The only thing that goes through the wall is a nipple that connects an 11B box with a 4 wire 50 Amp range receptacle inside to a weatherproof box with a twist lock inlet outside.
Picture that all by itself on the right side of an Optional Standby Panel which is wired like a sub panel (floating neutral) but is fed with a 50 Amp 4 wire range cord that hangs out of the bottom of that panel.
On the left side of the Standby Panel is the Service Equipment that has an 11B box nippled out of the bottom with a 50 Amp 4 wire range receptacle. The range cord from the Standby Panel is normally plugged into this receptacle.
When the utility power goes out the range cord is unplugged and plugged into the other 50 Amp 4 wire receptacle on the right side which is fed through the twist lock inlet from a cord plugged into a portable generator outside.
The 2 hots and the neutral are completely isolated from the Service Equipment. No back feed to utility workers.
A piece of #4 solid copper would bond the Service Panel and the Standby Panel and the Generator 11B box/inlet box together.
The equipment grounding wires can only come in contact with a grounded neutral at their source either in the Service Panel or in the Generator (if the generator frame and twist lock ground terminal are bonded to the neutral) which I think most of them are or they can be. Then the generator is a separately derived system which is the best situation. Right? The equipment grounds make a direct shot back to the source, in any situation. The #4 bond wire connects all the equipment together all the time no matter which source the 4 wire plug ground is plugged into.
The 2 hot wires are separated from the utility and can’t back feed from the generator.
The neutral is separated too.
I’m looking at a 2014 NEC here and it says under 400.7(6) Uses Permitted “Connection of utilization equipment to facilitate frequent interchange”
A panel is not utilization equipment but as I mentioned earlier electric panels in Mobil Homes are fed by cords so that does set an example to refer to.
The Standby Panel would have a back fed 50 Amp breaker with tie down bracket that the 50 Amp range cord is connected to.
It’s simple for the average person. No looking in the panel trying to switch over.
Turn off all the breakers in the Standby Panel.
Unplug the Range cord and plug it into the Generator receptacle.
Plug in the generator cord to the generator and inlet.
Start the generator.
Turn on the Main in the Standby Panel and select the loads.
My thinking is that in an emergency these materials would be available at one or the other of the big name hardware stores.
Of course they may not have power either so...
And the gas stations will be down too and I don’t think any of them have standby generators.
But it is a good option to have in mind, I think.
Would the local Authority Having Jurisdiction approve this?
 
1-I would not agree that wiring a generator as an SDS is preferred. I never wire them that way.

2-A Midwest or GE manual transfer panel is readily available, and extremely simple to use. I’m not sure what advantage there is to this rather convoluted system.

In fact, I usually keep a couple transfer panels and power inlet boxes in stock, especially during the winter.
 
I think most portable generators are floating neutral. Some may have a bond switch. It is usually easy to add a "bonding plug" if you want to bond the neutral and ground.
 
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The ones specifically designed for home standby use are usually floating.

Many that are intended for portable or job site use will be bonded, but it’s about a 30 second job to remove the bond.

Far quicker and easier than designing and installing an SDS.
 
Seven-Delta-FortyOne said:
1-I would not agree that wiring a generator as an SDS is preferred. I never wire them that way.
Click to expand...
Agreed. A common interconnected neutral makes everything simpler and easier.

Seven-Delta-FortyOne said:
2-A Midwest or GE manual transfer panel is readily available, and extremely simple to use.
Click to expand...
Disagree, because a whole-panel manual interlock is easier to install and operate.

Plus, it allows for powering almost everything up to the capacity of the generator.
 
LarryFine said:
Agreed. A common interconnected neutral makes everything simpler and easier.


Disagree, because a whole-panel manual interlock is easier to install and operate.

Plus, it allows for powering almost everything up to the capacity of the generator.
Click to expand...

Thats what I was referring to.

I won’t install the “critical circuit“ panels. 😡

The ones I’m talking about are the transfer panel only, where the entire feed is run through the transfer switch.

Like this one:

www.homedepot.com

ABB 200 Amp 240-Volt Non-Fused Emergency Power Transfer Switch TC10324R - The Home Depot

Run your backup generator with this UL recognized GE Non-Fused Emergency Power Transfer Switch. Features metal construction.
www.homedepot.com
 
Seven-Delta-FortyOne said:
The ones I’m talking about are the transfer panel only, where the entire feed is run through the transfer switch.

Like this one:

www.homedepot.com

ABB 200 Amp 240-Volt Non-Fused Emergency Power Transfer Switch TC10324R - The Home Depot

Run your backup generator with this UL recognized GE Non-Fused Emergency Power Transfer Switch. Features metal construction.
www.homedepot.com
Click to expand...
Still too expensive to buy and install, especially in existing installations.

I'm talking about these: https://interlockkit.com/

1701475456659.jpeg
 
LarryFine said:
Still too expensive to buy and install, especially in existing installations.

I'm talking about these: https://interlockkit.com/

View attachment 2568848
Click to expand...
LarryFine said:
Still too expensive to buy and install, especially in existing installations.

I'm talking about these: https://interlockkit.com/

View attachment 2568848
Click to expand...
Those are my favorite. 👍

Unfortunately, almost impossible to find around here, for the common Eaton panels that we have here.

Last 3 I’ve looked at, 2 of them there wasn’t an interlock available for that model, and the other was out of stock indefinitely. 😡
 
Seven-Delta-FortyOne said:
Those are my favorite. 👍

Unfortunately, almost impossible to find around here, for the common Eaton panels that we have here.

Last 3 I’ve looked at, 2 of them there wasn’t an interlock available for that model, and the other was out of stock indefinitely. 😡
Click to expand...
Interlockkit just happens to be here in Richmond. I'll ship to you if they won't.

They make them, so they should stock every model.

Shop Interlock Kit Products | Interlock Kit

Shop our top-tier Interlock Kits, ideal for any environment requiring a dependable, safe transition from grid to emergency backup power.
interlockkit.com interlockkit.com

You can always call them: 804-538-3184

Contact Us | Interlock Kit

Wondering if a generator interlock kit is right for your home? Get in touch with our team to learn more about our products.
interlockkit.com interlockkit.com
 
It looks like that interlock kit would come off along with the panel cover if the cover was removed. The back feed interlock has to be part of the construction even with the cover removed.
Cutler Hammer’s CH816GEN6060 stays in place when the cover is removed. The breakers sit on top of each other and a bar slides up and down blocking one or the other. It’s mounted to the back of the panel and holds the breakers down too for the back feed protection - NEC 408.36(D)
Reliance uses a bar that is tied onto both breaker switches, the breakers face each other.
There are many details to an Optional Standby Panel. Like if you fed one phase from a multi wire circuit in the Optional Panel and left the other phase fed from the utility panel... dang it.
And the unstitched neutral I’m pretty sure would create Objectionable Current NEC 250.6(A) because of Parallel Paths NEC 250.142 if the portable generator was a Separately Derived System with its neutral bonded to the grounding conductor and to the generator frame.
In the rubber twist lock cord it would be like two neutrals? Not too dangerous in the rubber cord but any metal along the way would be a potential parallel path.
And I’m of the opinion that the portable generator should be a Separately Derived System.
That’s why this range cord option has always intrigued me. It does look like Green Acres. But Lisa Douglas could probably do the plugging in, both inside and out and Ebb could pull on the generator rope if the battery was dead.
These Optional Generator Panels are not always that easy to get and have really increased in price.
5F0283A8-C1F6-44DE-8BEE-AA003907FF93.jpeg
 
Here’s the last one I just did with a dead front interlock.

Passed inspection just fine.

IMG_3509.jpeg

Im curious, do you install many generators as an SDS? What do you find the advantage to be?
 
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