Water Heater electrical code violation by design

[jar546]

I just caught this one in plan review and though I would add this as some trivia. Here is the situation.

Level 2 remodel of condo which includes a new water heater
The panel schedule showed the following:

A double pole 60A breaker with #6awg cu wire to a 4500w electric storage water heater.

What is the NEC violation? Cite the code please.

 

[Paul Sweet]

It's OK if the water heater is listed and wired for simultaneous operation of both elements.

 

[BN4537]

334.80 says that NM cable shall be sized according to the 60 degree C column (310.16), which allows 55 amps on a 6AWG wire.

422.11(E)(3) says the branch circuit for a storage type water heater shall not exceed 150% of the device's rated current if the overcurrent protection is not marked.

4500 watts / 240 volts = 18.75 amps. 18.75 amps x 150% = 28.125 amps.

They need a 30 amp circuit maximum.

2020 NEC

 

[jar546]

334.80 says that NM cable shall be sized according to the 60 degree C column (310.16), which allows 55 amps on a 6AWG wire.

422.11(E)(3) says the branch circuit for a storage type water heater shall not exceed 150% of the device's rated current if the overcurrent protection is not marked.

4500 watts / 240 volts = 18.75 amps. 18.75 amps x 150% = 28.125 amps.

They need a 30 amp circuit maximum.

2020 NEC

B I N G O

Since this is a condo, high-rise, however, there is no NM cable and more than likely this is in EMT with THHN.

 

[BN4537]

That was a good one, I probably would not have caught it on plan review.

 

[jar546]

We have problems with tankless being snuck in so we really pay attention to the panel schedule which we require.