Rust in panel box

Todays inspection showed rust in the panel box. There was also a rust covering on the lugs of several breakers and the throw lever locking bar on the four main breakers. The service line did not have any indication of moisture coming in from there.

Some of the breakers had been replaced, evidenced by shiny lug screws. Would some of this rusting occur if there was fairly active moisture in the basement? should all the breakers be replaced?


A free PDF download from the National Electrical Manufacturer’s Association (NEMA), “Evaluating Water Damaged Electrical Equipment”

Hi Marc,

Do I need to sign up to get it?


It’s a free download. They ask you to “register” by some means, which only takes a minute. Then, you’re signed up with them forever.


I have seen rusting at the bottom of a panel like that. In fact it was mine, and a few months later, it looked like this!

It was determined by the fire marshall that it was coming down the SEC. He said it is very common where they don’t enclose it in PVC, and in most cases, they loose the house. Fortunately I was home, in fact about 10 feet from it when it exploded. My new SEC is enclosed in PVC.

In my opinion, I would declare it a safety issue, tell the buyer and seller it needs to be fixed and as the NEMA document that Marc provided says, replace the breakers, definitly the main, and probably the SEC.

But then again, that’s my opinion (from experience).

What do you mean “enclosed in PCV”? There was no weather head?

It is common in many areas to use type SE cable (service entrance cable) in lieu of conductors in conduit. This method adds a few more potential places for water infiltration. The water will follow the conductors like a wick, and drip off inside the panel.

There are weather heads in both cases. However, the PVC setup is better. The weather head is one source of entry, the other is where the cable enters the meter trim. With PVC, it is sealed (cemented), with an SEC, it was 20 year old “putty” which is on my inspection list now. The other thing, on “the day of the event” we had a Nor’easter, 40-50mph winds with about 3-4 inches of rain. So there was no real consensus as to where the water got in, just that it did, then bridged the main and started working its way towards the meter until the utility came and cut the lines

Ok, I follow ya. Thanks Marc and Bruce. SE cable does not necessarily need to be “protected” in conduit if I’m following you correctly, hence the water penetration issue on the cable into the structure.

P.S. Bruce,
Last time I heard the term “Nor’easter” was when I used to live in Maryland. Man does that word bring back memories. They call the same type of weather out here, a “pineapple express” because of all the moisture coming up from the tropical south pacific.

I suspect that the breakers may have been replaced to gain more circuits in the panel depending on weather or not the runs are new. Someone could have corrected a double tap recently as well.

Just an observation, I am not warm and fuzzy about that double breaker at the bottom of the right pole. Has double tap on both sides which could be acceptable provided the breaker is the correct type, but the hot neutrals are not marked hot.

That burned up panel pic posted is SCARY.

Yea, it was. I was standing about 10 feet from it when it went. Gave me a new appreciation for “Arc Flash”.