I agree, as far as the NEC is concerned you cannot really overfill a panel.
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Thanks for that. I was always led to believe there was a limit. Is that something that has changed over the years, or just another ‘electrical myth’ by lowlife, ‘scumbag’, wannabe sparky’s scamming for work?
There has been as limit for as long as I can remember. It is hard to reach the percentage of fill allowed.
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In your opinion, what would be a ‘red flag’ for home inspectors to be aware of when this may be a legit concern? Excessive splices/pig-tails for example?
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Follow-up question: Does this rule change with Commercial electrical systems? Most of the Sparky’s that I come in contact with are on commercial jobs. Most on Residential are just idiots. It’s been a long while since I’ve been informed about the fill level, and have no clue where I’ve learned it. Just trying to sort it out to correct what I’ve thought was fact. Thx.
Fill levels are the same for commercial and residential. Commercial gutters are typically larger.
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Agree, and do I rarely ever see one that even hints at being at capacity. Perhaps that is why the perception of being overfull on residential. Thanks for your input.
I cannot find a limit for a panelboard enclosure in the NEC. Panelboard cabinet gutter space is governed by the bending radius requirements in 312.6. If the enclosure contains splices or taps the maximum fill is 40% for conductors and 75% for splices and taps at any cross-section. It would be nearly impossible to even reach a 40% fill level.
For example say the gutter space is 4" x 3.5", that would be an area of 14 square inches.
14 * 40% would be a maximum fill of 5.6 square inches. A #12 THHN conductor has an area of 0.0133 square inches.
5.6/.0133 = 421 #12 THHN conductors to reach the 40% fill limit. So for all intents and purposes the cabinet cannot be overfilled.
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That’s true of newer residential panels compared to older panels as well.
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Yes, an residential panel is about 14.25" X 4" and is designed to go between two studs. A typical commercial/industrial panel is 20" wide and 6" deep.
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More than being overcrowded since it looks like they only used the available spaces , i see it as a bit messy . The other thing that i never saw is that the main service breaker/s are on the bottom . I have never seen one like that . Could it be that it was installed upside down ? or it could be that in different parts of the country these panels are used . Generally i would not really call it as a defect but would ask a licenced electrician to verify before my report goes out .
If the circuit breaker is at the bottom of the panel but the closed position (ON) is with the handle up then there is nothing to verify.
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I guess you’re right . I just never saw a panel with the main on the bottom . Thanks .