Spliced Ground

I found a spliced Ground in the main panel. I called it out and just wanted to make sure I was correct. I have never come across this before.


**© Continuous. **Grounding electrode conductor(s) shall be
installed in one continuous length without a splice or joint
except as permitted in (1) through (4):

(1) Splicing shall be permitted only by irreversible
compression-type connectors listed as grounding and
bonding equipment or by the exothermic welding

(2) Sections of busbars shall be permitted to be connected
together to form a grounding electrode conductor.

(3) Bonding jumper(s) from grounding electrode(s) and
grounding electrode conductor(s) shall be permitted to
be connected to an aluminum or copper busbar not less
than 6 mm × 50 mm (1⁄4 in. × 2 in.). The busbar shall be
securely fastened and shall be installed in an accessible
location. Connections shall be made by a listed connector
or by the exothermic welding process.

(4) Where aluminum busbars are used, the installation
shall comply with 250.64(A).

A little housekeeping wouldn’t hurt either :wink:

It is defnintely not a job for a wire nut !! However, most HIs would probably not catch the distinction as to the type of connection permitted. A very good education thread for us all.


Is that dirt or just a massive build-up of dust over the years?

No…that looks like a standard wirenut.

Remember the concept is this…if lighting or transient voltages as well as potential higher voltage sources ( how ever you would like to call it) gets imposed onto the GEC and hits that wirenut it will melt open and defeat its purpose…now and in the future.

Read Joes NEC statements…notice all methods maintain a constant connection during the event…a wirenut does not in this situation.

So Paul / Electrical Gurus of NACHI :mrgreen: -

When exactly is a wirenut allowed in a service panel?

I see them quite a bit in the following circumstances:

  1. A branch circuit is too short due to a replaced service panel or moving a breaker to another location. So, it’s one 12awg from the circuit and one 12awg to the 20amp 120 breaker.

  2. Two 15 or 20 amp branch circuits are needed but they only have one breaker of the appropriate size (usually double lugged but in rare cases), their will be 2 12awg from the circuits and one 12awg to the 20amp 120 breaker.

I don’t see them often on neutral or ground wires, but I do see them double, triple, … lugged quite often.


Happy Holidays All!


It is not that wirenuts are not allowed in panels. The problem shown here is with its’ use to extend the grounding conductor. Please read post #2 to see the Code accepted methods if a grounding conductor needs to be spliced.

Wirenuts used to extend the branch circuit wiring as in your two examples are fine. There are limits on cross-sectional fill area, like how many wires can be in a box, however, you would really need quite a few connections in the same area to exceed this rule.

This is a potentially confusing thread. The GROUNDING ELECTRODE CONDUCTOR shall not be spliced except as noted in JT’s post above. An EQUIPMENT GROUND can be spliced using a wire nut, as can a grounded or ungrounded conductor.

There is no prohibition to using wire nuts in the serivce panel.

Thanks guys, just wanted to make sure I was understanding it…

Thanks, this is very important, the correct terms and definitions should always be used, especially in any reports.

The issue about the splicing in any cabinet is better described by the rule:

lol…typical students of the Code…lo

  1. nothing was ever said about wirenuts in a panel. The statement was made that the wirenut shown does not meet the requirements of the GEC being with splices…

  2. The NEC prohibits splices in a panel enclosure with switches or overcurrent devices…But makes allowance for them if the space is provided and does not exceed 75 percent of the enclosures cross sectional values…most panels will allow for this space so it is not an issue.

Again its important to understand the thread…someone i believe implied a statement that splices are not allowed in a panel…however i digress…either way this splice (wirenut) is not allowed because this connection is not allowed.

I can also promise you that in the event of lightning imposed on that GEC…that splice will melt like butta…thus removing the required connection to the GE.

again this thread should not have morphed into a wirenut in panels issue…by now all HI’s should know splices in a panel are allowed…hard to ever have a service change without any.

If you really had “lightning” on that GEC it wouldn’t matter if it was CadWelded. Lightning will not make a 180 degree turn. It would just shoot out the end. That is why air terminal conductors need to be run as straight as possible with very wide radius turns. Generally you will not really get lightning in a panel and if you do it will be toast. I did take a direct hit on the air terminal above my weather station this summer with minimal damage.

I am reminded of this rule:

**"280.12 Routing of Surge Arrester Grounding Conductors.

**The conductor used to connect the surge arrester to line, bus, or equipment and to a grounding conductor connection point as provided in 280.21 shall not be any longer than necessary and shall avoid unnecessary bends."

. and on another note, the original picture shows signs of dirt in the bottom, this could be because of a flood, and if so, the weep holes in the bottom of the cabinet may be plugged up.

Thanks Paul

look…no one can predict what lightning will do, Can do or assume will do. There is a reason this connection should not be spliced and if done so in a proper manner.

Quite possible your good connectiom is the aid in why you had little or no damage…lightning is an amazing thing…but in regards to code…everything in my mind has its place.

Direct hits will have its way…but with proper bonding of systems and meeting the requirements may not save the equipment but might save the house…lol

Great info. gentlemen.

Simply look for an irreversible splice which is a splice the cannot be reversed, or removed. Such as a set screw splice, or a mechanical splice.

Nuff said…

The main secret in lightning protection is bonding and grounding lots of bonding and grounding.
I spent some time with the engineer Florida hired to protect the toll booth on I75 going into the west end of the Everglades. You might not think of that being a target but it is just about the only thing poking up in the air for miles around. They are also stuffed with computer equipment and other electronics, spread out along the row of toll booths. The short answer is lots of copper, Ufers and 40’ ground rods. The duct banks themselves are also electrodes since the 2/0 copper GECs run through them, in contact with the 5x5 concrete matrix (each) and 10’ underground.
At my house I have 3 rods, a Ufer under the garage and a huge Ufer (the pool and deck with footer) along with 60 or 70 feet of buried copper wire. My air terminal has a 2/0 copper going to the electrode. The shot I took was exciting, we were out in the pool bar when it happened, but fairly uneventful electronically.
I am blaming it for the bad serial port on the “weather” PC and the bad temp sending unit in the weather station but both took a week to show up bad.

Set screw connections are not irreversible. Compression type connections would be.

Don’t forget it is OK to use a busbar as part of the GEC so if someone added a busbar right where that splice is it would be “hold your nose” legal.
If you can sweet talk the PoCo guy into crimping on one of his ground wire splices that is legal too. (look at a power pole ground wire and you will usually see one … or more)