Unusual Sub-Panel Wiring


I saw an unusual method of wiring a sub-panel yesterday. The feed from the main panel is wired to the terminals of the 50 amp breaker in the sub-panel and not the normal Bus terminal lugs.

I assume that this is an attempt to create a “main” in a panel that does not have a main breaker attachment. The circuit is also protected by a 50 amp breaker in the Main Panel.

Is this acceptable?

Note: I am reporting the open knockouts.

The panel is being “back-fed” through the breaker. Not uncommon. . .

The backfed breaker should be fastened in place. 384-16 (g)

In addition:

Markings on panelboards that employ plug-on units require the use of a hold-down kit when the units [FONT=Arial]are back-fed and the field installed supply conductors are terminated on the plug-on unit. The marking indicates: “Back-fed _____ requires hold-down kit Cat. No._____ “ or the equivalent.

An identification of the applicable back-fed unit is specified in the first
[size=3]blank-for example, circuit breaker, fused switch, or terminal kit; and the catalog number of the required hold-down kit is specified in the second blank.

Reference: UL Panelboard Marking Guide and Industry Standards

Back-Fed Devices

Plug-in-type overcurrent protection devices or plug-in type main lug assemblies that are back-fed and used to terminate field-installed ungrounded supply conductors shall be secured in place by an additional fastener that requires other than a pull to release the device from the mounting means on the panel.

I don’t see this “kit” in the picture?

This rule has been in the industry standards for at least 10 years, because of an electrocution…[/size][/FONT]

Ok…Timothy…I am going to ask one question here not related to what has been posted.

Q: What size was the conductor that FED the panel shown here?

I will tell you why when you reply…Now i know what should be installed for the 50A breaker…and we all know the conductor can be larger…I just would like to know what size the wire was to this panel.

Paul, you realy have me wondering what your going to say. I’m posting to track this thread in my email.

lol…well it really depends on what Timothy tells me here…lol

Besides…I may have nothing as pictures are sometimes not great for thinking you see things…so I just want to know for piece of mind but I will wait for Timothy to let me know.


#6 copper THHN in plastic? (at least going in the ground and out of the ground) conduit buried - 4 leads - 50’ from the main Panel.

The panel is mounted in a storage shed on a dock.


Thanks Timothy…Next Question…

Is that GREEN TAPE wrapped around the Ground Wire?


No, it is pvc insulation.


Cool…thats why I did not want to post anything and wanted to ask the question because pictures sometimes dont tell the story…with the BRIGHT color of that cable…I have only seen it that bright when it was wrapped with Green Tape…which in the NEC would not be allowed on 6AWG and smaller cables…The risk of that is someone later can come along later and remove the tape and screw something up.

Anyway…I have learned…asking the questions is better than just posting since I could not zoom in on the picture…looked like tape sticking up on the end about 1 inch before it goes into the terminal block.

Anyway…Just wanted to check…:slight_smile:

Thanks for the info. Joe & Brian, I KNEW that something didn’t look right. Thanks for the reminder.

Around here, a back-fed breaker is usually a DIY emergency generator connection point.

Thanks again, TG

It also looks as if a knock out is missing from the top of the box, and the copper pipe should also be capped just in case it is just attached to a shut off valve, and if the valve leaks…