Electric Vehicle Charger Installation Inspected and Failed

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BMacky

Senior Member
Location
Foster City, CA
From my customer, for whom I installed an EVSE last week. Manufacturer listing says max output is 30A. I assume this would be the max load, correct? Anyhow, here's what's up for comment:

"Had the inspector out a few minutes ago. He wants us to make one change.
The manual says a 40 amp breaker and that's what we have. But the guy said code requires 10% more than expected load. So we have to bump up to a 50 amp breaker.

The tag on the charger says it takes 30A. On the web I find a spec sheet (attached PDF) that says "Input Current 40A Max". So I guess this is a matter of interpretation. And it's the inspector's interpretation that matters."

Anyhow, that varies from 625.21 by 15% if I understand what the inspector thinks he's referring to. Is there any other applicable Code here, or am I misinterpereting max load?

I was not at the inspection, so could not get any clarification.

Thanks for any review comments.

Bob
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
From my customer, for whom I installed an EVSE last week. Manufacturer listing says max output is 30A. I assume this would be the max load, correct? Anyhow, here's what's up for comment:

"Had the inspector out a few minutes ago. He wants us to make one change.
The manual says a 40 amp breaker and that's what we have. But the guy said code requires 10% more than expected load. So we have to bump up to a 50 amp breaker.

The tag on the charger says it takes 30A. On the web I find a spec sheet (attached PDF) that says "Input Current 40A Max". So I guess this is a matter of interpretation. And it's the inspector's interpretation that matters."

Anyhow, that varies from 625.21 by 15% if I understand what the inspector thinks he's referring to. Is there any other applicable Code here, or am I misinterpereting max load?

I was not at the inspection, so could not get any clarification.

Thanks for any review comments.

Bob

If the manufacturer calls for a 40A breaker, chances are that is the maximum value allowed that will still provide protection to the load. Similar to a motor which llists maximum OCPD. IMHO you can't just go higher that that based on some speculation about the equipment.

40 is well above 110% of 30. Anything more than 30 will be transient start up surge, etc. and the breaker thermal curve will allow that.
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
Bet Placerville was a cooker last few days!
Never over 98F up here at 2500' elevation. The flatlanders cooked in spite of the delta until an onshore breeze started up yesterday. Only 85F outside my office window. And dry enough that an evaporative cooler can produce a 20F air temperature drop.
 
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