Branch circuit wire size and overcurrent protection quandary!

Status
Not open for further replies.
Jon456

Jon456

Senior Member
Location
Colorado
Finishing up the install on a duel-pump fuel dispenser. Wiring was done in accordance with the dispenser manual. These are the circuits from the subpanel supplying the dispenser:

1. Control power, 120VAC: one pair of 14 AWG on a dedicated 15A breaker to power the dispenser electronics.
2. Suction pump motor power, 240VAC: one pair of 10AWG on a dedicated 2-pole 20A breaker to power both pump motors. (Only 12AWG was required.)

This dispenser is fed from two Aboveground Storage Tanks (ASTs) and the dispenser has two pairs of wires in its junction box for activating (powering) each of the anti-siphon solenoid valves at the top of the tanks. Each solenoid draws less than 1A. According to the dispenser manual: "Wire for solenoid control is recommended to be 14 AWG." So that is what was installed.

I've since discovered that the power for each of the solenoid control wires is tapped directly off the power leads to its respective pump motor inside the head of the dispenser. (I had originally incorrectly assumed that the solenoids would be powered from the dispenser control circuit.) There are no additional fuses or breakers inside the dispenser head to provide additional protection on these solenoid wires. That means the 14 AWG solenoid wires are only protected by the 20A breaker in the subpanel.

Is this acceptable? If not, why would the dispenser manual recommend 14 AWG wire for the solenoids?
 
It's pretty common to see internal wiring for equipment that utilizes conductors that are small than required by the NEC. But it sounds like your asking about field wiring that's an extension of the equipment wiring being recommended as #14 AWG on a 20 amp OCPD?
 
infinity said:
It's pretty common to see internal wiring for equipment that utilizes conductors that are small than required by the NEC. But it sounds like your asking about field wiring that's an extension of the equipment wiring being recommended as #14 AWG on a 20 amp OCPD?
Click to expand...
Exactly. The factory-installed wires in the dispenser's main junction box for the solenoid circuits appear to be only 16 AWG. But I'm talking about the field wiring we installed from the dispenser's main junction box to the solenoids at the tanks. The dispenser manual specifically recommends using 14 AWG. They didn't even use the word "minimum" in their recommendation.
 
I just got off a 15 min phone call with the dispenser manufacture's tech support. Ultimately, they couldn't give a reason for the manual's wiring recommendations. The second person I spoke to finally gave up and said, "Just comply with your local authority requirements."

At this point, I think I'm just going to have to pull out the two pairs of 14 AWG wire and replace with 12 AWG. :weeping:
 
Jon456 said:
I just got off a 15 min phone call with the dispenser manufacture's tech support. Ultimately, they couldn't give a reason for the manual's wiring recommendations. The second person I spoke to finally gave up and said, "Just comply with your local authority requirements."

At this point, I think I'm just going to have to pull out the two pairs of 14 AWG wire and replace with 12 AWG. :weeping:
Click to expand...

that is probably the simplest solution.
 
Status
Not open for further replies.
Top