60 Amp Spa Disconnect 6/3 NM-B 240.4(b)?

[MKerrigan90]

Installing a hot tub.

Hot Tub Nameplate:
240v
Circuit Breaker: 60 Amps
Current Draw: 45Amps

60 Amp breaker in the main panel will feed spa disconnect with 6/3 romex located on the outside wall of the house. A 60 Amp GFCI breaker will provide the branch circuit to the hot tub with 2 #6 THHN with #10 grounding conductor in pvc conduit. My question is about the 6/3 romex, does 240.4(b) apply? 6/3 NM-B at 60º is 55 amps.

 

[augie47]

Installing a hot tub.

Hot Tub Nameplate:
240v
Circuit Breaker: 60 Amps
Current Draw: 45Amps

60 Amp breaker in the main panel will feed spa disconnect with 6/3 romex located on the outside wall of the house. A 60 Amp GFCI breaker will provide the branch circuit to the hot tub with 2 #6 THHN with #10 grounding conductor in pvc conduit. My question is about the 6/3 romex, does 240.4(b) apply? 6/3 NM-B at 60º is 55 amps.

Clarify please. Is the Romex located on the outside wall of the house ??

 

[Little Bill]

Installing a hot tub.

Hot Tub Nameplate:
240v
Circuit Breaker: 60 Amps
Current Draw: 45Amps

60 Amp breaker in the main panel will feed spa disconnect with 6/3 romex located on the outside wall of the house. A 60 Amp GFCI breaker will provide the branch circuit to the hot tub with 2 #6 THHN with #10 grounding conductor in pvc conduit. My question is about the 6/3 romex, does 240.4(b) apply? 6/3 NM-B at 60º is 55 amps.

Yes, you are limited to 55A with NM.

Clarify please. Is the Romex located on the outside wall of the house ??

Moot point about inside or out as far as the ampacity, but correct if you're talking about the NM not allowed outside.

 

[infinity]

Next size up rule is 60 amps?

 

[MKerrigan90]

Romex is not exposed on the outside wall. Sleeved in a short piece of PVC conduit less than 24". The main panel is in the basement. PVC conduit to the tub is not installed yet. Hot tub has not arrived. 55 amp breakers are not standard per the NEC table.

https://drive.google.com/file/d/1nqrhz5wt6HYpMKXqKNclbCaopH6IXu-2/view?usp=sharing

 

[Little Bill]

Next size up rule is 60 amps?

Yes, but the spa says 45A and 45x125% = 56.25A
To use the next size up rule, you can't go over the current draw of 55A.

ETA:
to put it simpler, the load is limited to 55A

 

[Buck Parrish]

Next size up rule is 60 amps?

Yes 240.4 (B)

Although all most all the hot tubs I've done the directions say to use #6 on a 50-amp breaker. So, you may be on to something. Does the OP have the directions? Or just going by the name plate?

 

[Little Bill]

Romex is not exposed on the outside wall. Sleeved in a short piece of PVC conduit less than 24". The main panel is in the basement. PVC conduit to the tub is not installed yet. Hot tub has not arrived. 55 amp breakers are not standard per the NEC table.

https://drive.google.com/file/d/1nqrhz5wt6HYpMKXqKNclbCaopH6IXu-2/view?usp=sharing

You would need to check with your AHJ as to whether they will allow the short section of NM outside even though it is in conduit. Inside conduit outside is considered a wet location. some areas will allow a short piece outside.

 

[infinity]

Yes, but the spa says 45A and 45x125% = 56.25A
To use the next size up rule, you can't go over the current draw of 55A.

ETA:
to put it simpler, the load is limited to 55A

Are spas required to be considered a continuous load?

 

[Little Bill]

Are spas required to be considered a continuous load?

It's the motor that requires the 125%. I know I have connected spas that said 40A but specs said use a 50A breaker. Same thing with a spa that said 48A but a 60A breaker was required.
40x125%=50A
48x125%=60A

 

[MKerrigan90]

I do not believe a hot tub to be a continuous load. Every component would have to be on for more than 3 hours. Lights, jets etc.

 

[MKerrigan90]

Model Hot Tub is J-280

https://staging-na01-jacuzzi.demand...s/j-200-english.pdf?version=1,599,144,973,000

 

[infinity]

I do not believe a hot tub to be a continuous load. Every component would have to be on for more than 3 hours. Lights, jets etc.

I agree. Take the nameplate rating of 45 amps and size the circuit accordingly.

 

[wwhitney]

FWIW, from the manual:

Cheers, Wayne

 

[infinity]

FWIW, from the manual:

So using those numbers and the third configuration, the OCPD is 60 amps, the load is 45 amps. Going back to the OP #6 NM cable is 55 amps, next size up rule 60 amp OCPD.

 

[wwhitney]

Right, but the question is why the manufacturer's OCPD sizing specifies OCPD >= 125% * load in all cases. I guess the manufacturer may be thinking it's a continuous load, but is mistaken?

Cheers, Wayne

 

[infinity]

Right, but the question is why the manufacturer's OCPD sizing specifies OCPD >= 125% * load in all cases. I guess the manufacturer may be thinking it's a continuous load, but is mistaken?

Don't know, maybe they just want some headroom. The #6 NM would still be code compliant.

 

[Little Bill]

Wouldn't sizing the circuit like you do for a motor or motors where you take 125% of the largest motor and 100% for the rest be what they were thinking? Or just 125% if only one motor?

 

[MKerrigan90]

I take it, I am good with 6/3 NM feeding the spa disconnect, just wanted a second opinion.