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I'm in the process of a DIY 400A service upgrade, I roughly wired up the main panel waiting for the utility to schedule the switchover to the new line.

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For now I have installed a single 125A breaker that I will need to continue have power in the house. The black wires come from a box on the inside. I have marked the neutral with some random white tape and one of the phases with duct tape.

The copper wires go to the Ufer ground. As I had wire in excess, I ran two. The city inspector already approved the ground connection but hasn't seen the other wires.

Are the wires tidy enough? Should I square them up more? The 125A breaker output has flat-blade screws like if it was designed in the 19th century - I need to properly torque those down.

What I am concerned about is that this main panel will only be used to install few more 125A breakers (plus the second 200A above). There aren't many neutral connections for larger size wire.

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    It might be too tidy. Wires usually do not have such tight bends.
    – crip659
    Commented Feb 5 at 17:11
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    Are you asking for a review of your work prior to the inspection, or is something not working properly and you're trying to figure you what it is? Also, "Ufer", not "U.F.E.R". It's named after the guy who invented it, not some evil spy organization...
    – FreeMan
    Commented Feb 5 at 17:17
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    @crip659 you may be considering the wires that came with the panel (top section). I never touched those. Commented Feb 5 at 17:45
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    I would think that "random white tape" and duct tape would be inappropriate for wire marking. You're spending a lot of cash on this heavy up, use some quality electrical tape. The extra buck or two will disappear into the overall project cost.
    – FreeMan
    Commented Feb 5 at 18:00
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    @crip659 The wires with the 90˚ bends are factory-installed and covered by the panel's listing. There is no issue with those.
    – nobody
    Commented Feb 5 at 23:03

2 Answers 2

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Three problems for sure:

  1. Duct tape is not listed for marking electrical wires. When using tape, you must use UL-listed tape. (The same rule applies to the white tape on the neutral but it looks "close enough" to legitimate electrical tape that an inspector probably wouldn't question it)
  2. Gray is not a valid color for marking hot wires. Gray is reserved for neutral, along with white. There isn't actually a requirement to give distinguishing marks to the two hot wires on a 240V split-phase circuit, so you could just remove the duct tape and be fine.
  3. The #4 ground wire going inside isn't marked. It needs to be marked green.
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    Duct tape has flammable fibers in it for added strength. You can see someone using duct tape to start a fire. Not exactly something you want in a panel.
    – Nelson
    Commented Feb 6 at 7:33
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    Duct tape also has a tendency for the glue to dry up and cease to stick to anything, therefore falling off or sliding to where it's unable to be read. Commented Feb 6 at 18:02
  • I asked my wife what was the white tape she gave me and she said it's the tape used to keep gauze in place when you have a cut. I have placed an order for a set of Super35 in a variety of colours Commented Feb 8 at 6:35
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As @nobody points out, get rid of duct tape, mark your grounding wire green. If you notice, right behind where your wires connect to 125A breaker, there is a large gauge lug, possibly 2. There is also a whole neutral/ground bus on right hand side of panel. I would relocate your neutral and grounding conductors to right side, leaving the space on left clear for the remaining conduits. The #4 Grounding Electrode Conductors can be terminated in the bus on the right as well. However I believe you stated you installed 2 Ufer's? If so, you will still need at least 1 driven ground rod, 5/8" x 8' minimum. Code requires 2 grounding electrodes, ONE of which must be a driven ground rod. From what I can see, you should have 5 or so lugs still open that will accept at least 1/0, if not, home Depot carries lugs designed to attach to the bus for extra large gauge connections.

Nec 250.52 and 250.53 cover grounding electrode requirements. A single electrode can only be a rod, pipe, or plate type and to not require a supplemental electrode, must be verified to be maximum 25 ohms to ground. Your concrete encased electrode (ufer) is an acceptable supplemental electrode.

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    The two copper wires go to the same Ufer. I forgot the details when I looked it up before, but I thought the Ufer alone is plenty. The city inspector already checked that part, so now I'm a little confused why I would need an additional rod. Do you have the code number so that I can try to look it up? Commented Feb 6 at 6:41
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    "Code requires 2 grounding electrodes, ONE of which must be a driven ground rod." Where does the code say that?
    – Mark
    Commented Feb 7 at 20:46
  • @Mark -- the answer's misreading the applicable Code -- it's only water pipes and made rods/pipes/plates that require the supplemental rod. An Ufer, structural steel-in-soil ground, ground ring, or metal well casing ground is sufficient by itself. See NEC 250.53(A)(2) and (D)(2) for details Commented Feb 8 at 1:20
  • @AlessioSangalli -- the Ufer is definitely plenty! Commented Feb 8 at 1:20
  • @ThreePhaseEel Thank you. My recollection was that an Ufer ground was considered the ultimate grounding system, so the need for something else didn't make sense.
    – Mark
    Commented Feb 8 at 1:43

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