Hot tub wiring

[TexasMaster]

While estimating a hot tub circuit add I noticed a name plate stating "40 amp max load" "50 amp max breaker". Since I know the load and saw the pumps are thermally protected, do I get the exception of a motor driven appliance and get away with 8/3 romex (40amp in the 60deg) on a 50 amp gfi? Vd has been calculated and is not a concern. Just curious of others opinions or if that exception doesn't apply here. Thanks

 

[augie47]

Although I realize a motor is involved, I would have to see some more documentation before I would want to allow a #8 NM on a 50 amp breaker.
As a side note there is something in the back of my mind ( I believe it's manufacturer's requirements ) that call for a full size (same as phase conductor) equipment ground,. You might check.

 

[edlee]

do I get the exception of a motor driven appliance

No. There is a big resistive heater in there.

 

[TexasMaster]

No. There is a big resistive heater in there.

I guess I'm still missing something here. Any code reference to exclude hot tubs or motor operated appliances that also contain heating elements from 240.4g? I'll double check sometime, but I'm pretty sure theirs fuses to the heater in the control board as well as thermals in the motors. I'm just not seeing what's preventing someone from wiring to the load and breaker to max like an a/c.

 

[augie47]

You highlighted the problem I see. 240.4 states conductors will be protected at their ampacity except......
I don't see where a hot tub would be listed in 2340.4(G)

 

[FionaZuppa]

hmmm, my manufactured spa documentation says "North America 240v, 60Hz, 50A". i run 3x#6 + 1x#8(gnd) from service panel ~100ft to a disco/breaker panel, and then from there its ~20ft all #8 to the spa unit itself. service panel has std 50A breaker, remote panel has 50A GFI.

 

[Dennis Alwon]

hmmm, my manufactured spa documentation says "North America 240v, 60Hz, 50A". i run 3x#6 + 1x#8(gnd) from service panel ~100ft to a disco/breaker panel, and then from there its ~20ft all #8 to the spa unit itself. service panel has std 50A breaker, remote panel has 50A GFI.

Nevermind