Question about conduit fill percentage for wiring in 240v oulet

[GodsPeace]

This question is for someone who hopefully knows the answer to what is the max fill percentage one can legally fill a conduit with wires. I have an EMT conduit running from the main panel in a bedroom to a junction box in the ceiling of my garage. It already has three 14 gauge and two 12 gauge. I used a conduit fill calculator Conduit Fill Calculator - Best Online Conduit Fill Calculator to figure I'm under 43% if I run two additional 8 gauge wires. When I looked up the California code California Code of Regulations, Title 8, Section 2760. General. I see 50% max so I should be fine. I just wonder if it's supposed to be 40% since I've seen that number referenced in discussions but maybe that's more of an industry standard.

On a side note I have 2 different breakers energizing my livingroom, 1 bathroom, and garage simultaneously so maybe I can lose one of the conduit wires. Need to figure that one out first. I think they built the townhouse that way by accident. I've seen funky things done where I live so it wouldn't surprise me. I turn one breaker off and one on in any combination and all outlets and switches work. I'm going to try to trace the wires and see. One hot wire off one breaker is yellow so that should help, but yellow I think it supposed to be for a ceiling fan or switched power and no ceiling fans are present. The yellow one goes into the garage so I'll pull all the switches(one) and outlets(two) and see if there is a black hot wire coming in from another side then can disconnect either and test.

 

[mongo]

This question is for someone who hopefully knows the answer to what is the max fill percentage one can legally fill a conduit with wires. I have an EMT conduit running from the main panel in a bedroom to a junction box in the ceiling of my garage. It already has three 14 gauge and two 12 gauge. I used a conduit fill calculator Conduit Fill Calculator - Best Online Conduit Fill Calculator to figure I'm under 43% if I run two additional 8 gauge wires. When I looked up the California code California Code of Regulations, Title 8, Section 2760. General. I see 50% max so I should be fine. I just wonder if it's supposed to be 40% since I've seen that number referenced in discussions but maybe that's more of an industry standard.

On a side note I have 2 different breakers energizing my livingroom, 1 bathroom, and garage simultaneously so maybe I can lose one of the conduit wires. Need to figure that one out first. I think they built the townhouse that way by accident. I've seen funky things done where I live so it wouldn't surprise me. I turn one breaker off and one on in any combination and all outlets and switches work. I'm going to try to trace the wires and see. One hot wire off one breaker is yellow so that should help, but yellow I think it supposed to be for a ceiling fan or switched power and no ceiling fans are present. The yellow one goes into the garage so I'll pull all the switches(one) and outlets(two) and see if there is a black hot wire coming in from another side then can disconnect either and test.

Besides fill, your other issues are derating due to multiple current carrying conductors and pulling wires with 5 already in the pipe.

Fill:
1 wire :53%
2 wires: 31%
3 or more: 40%
National Electrical Code explanation: Conduit Fill

 

[GodsPeace]

Besides fill, your other issues are derating due to multiple current carrying conductors and pulling wires with 5 already in the pipe.

Fill:
1 wire :53%
2 wires: 31%
3 or more: 40%
National Electrical Code explanation: Conduit Fill

Thank you. After more reading I found multiple conduit fill calculators so with 2 14 awg, 2 12 awg, and 2 8 awg I was at 39.23% fill Conduit Fill Calculator - Best Online Conduit Fill Calculator . I'm only running 32 amps max through the 8 awg wires with a 40 amp breaker and when I felt the wires they seems like room temp but maybe just above. I'm getting 33 miles per hour charge which is more than enough. If I help my neighbors in the complex I'll suggest just 30 amp breaker for 24 amp charging. That really all I need but figured I can dial it down anyways.

 

[Mooeymoose]

Here you say 2 14awg but first you said 3 14awg. I guess it does not make much of a difference but it is a tight fit and it maybe hard to get all those wires in if you have a few bend but sounds like you did that already too. The other pieces to note is 32 amps is the max I understand 8 gauge can handle for charging. 80% max allowed for continues charging. I assume we are talking copper wire and not aluminum too.

 

[GodsPeace]

Here you say 2 14awg but first you said 3 14awg. I guess it does not make much of a difference but it is a tight fit and it maybe hard to get all those wires in if you have a few bend but sounds like you did that already too. The other pieces to note is 32 amps is the max I understand 8 gauge can handle for charging. 80% max allowed for continues charging. I assume we are talking copper wire and not aluminum too.

Yes I removed one 14awg wire. I discovered someone before me so before 2002 ran a wire connecting two different circuits in the house. I found it when I moved the 15amp breaker so they were on different phases so when I flipped the power it, it shorted =/. Then I followed all the wires and found that out so I removed one of them so they are not connected. Sliding one 8awg wire was easy, it was the 2nd one that was a biotch. I lubed it and worked it for a while then it went through. The Tesla charger maxes at 32amps so all good. 8 gauge can handle more but there is a rule that we shouldn't exceed 80% of a wires capacity and definitely not continuous flow. It's more to do with the insulation vs the copper. You can get 10awg wires rated above 30amps but probably not what Home Depot sells.