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I just got the results of a home inspection where they claim there is mismatched breakers and wires in my electrical panel. Specifically, the range (40A breaker) and heat pump (50A). He claims the wires are 30A.

Assuming this is true, is this a code violation (Nebraska)? Or a safety issue?

-edit- adding more info here for future readers so they don't have to read all the comments.

The heat pump had been replaced within the last 2 years. I called the company who installed it and they claim the heat pump installed only pulls 27A max but they would send an electrician out to swap the breaker that they missed. When the electrician came, he discovered that the 2nd over-sized breaker was not for the range (range was on a 50A wire with 50A breaker) but instead it was on an unused circuit that lead to the newly installed furnace (capped inside the furnace housing, just there for "future expansion"). Both breakers ended up getting swapped for free.

kinar
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2 Answers2

39

Was the bozo that wired those circuits trying to burn your house down?

Assuming that the wires are 10AWG (i.e. 30A), this is a major problem indeed as the wires can overheat badly from excessive current draw before the breaker ever notices something is wrong! Think of what a live toaster element inserted into your wall would do...

As to the Code, your issue violates 210.19(A)(1):

(1) General. Branch-circuit conductors shall have an ampacity not less than the maximum load to be served. Conductors shall be sized to carry not less than the larger of 210.19(A)(1)(a) or (b).

(a) Where a branch circuit supplies continuous loads or any combination of continuous and noncontinuous loads, the minimum branch-circuit conductor size shall have an allowable ampacity not less than the noncontinuous load plus 125 percent of the continuous load.

(b) The minimum branch-circuit conductor size shall have an allowable ampacity not less than the maximum load to be served after the application of any adjustment or correction factors.

and 240.4 (the exceptions in A-G do not apply to your case):

240.4 Protection of Conductors. Conductors, other than flexible cords, flexible cables, and fixture wires, shall be protected against overcurrent in accordance with their ampacities specified in 310.15, unless otherwise permitted or required in 240.4(A) through (G).

ThreePhaseEel
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Breakers and fuses are designed to be the weakest parts of the circuitry. It is their feature. Period.

They are designed to fail safely. Fuses burn literally, breakers safely discontinue the circuit.

If they are oversized, they may not be the weakest points anymore. In case of failure they won't be the first to burn - it may be the most expensive device you own or, even worse, it may be a conductor in the wall.

In that situation, instead of an annoying blackout (breaker) or burnt $8 fuse, you have lost your vintage $500 stereo or you have set your house/flat on fire.

tl;dr Buy 25A or, if really necessary, 30A breakers ASAP. Preferably yesterday.

Shadow
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Crowley
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