HPWC fail

[mswlogo]

Circular lugs usually have a circularly-shaped hole in a block of aluminum, with a screw piercing at a right angle to the circular hole, and squeezing down into the wire. It has the advantage that the screw actually separates the strands and squeezes them against the circular wall of the aluminum block, thereby enlarging the contact area between wire and lug/screw, as well as increasing the local force on the wire strands, which also improves the contact area (because copper is somewhat malleable). A've attached a picture of an uncaptured lug from my electrical panel that's UL-rated for 00 to 4 AWG wire, a pretty wide range of wire size. Other similar lugs are rated for 6 to 14 AWG, also a pretty wide range of wire size.View attachment 509244

But the Wall Connector supports 15A to 100A !!

 

[Sophias_dad]

IMHO, that's 8 gauge wire in conduit, and shouldn't be on a 60 amp breaker EVER. A 50 amp breaker would be okay, but you ALSO need to turn the HPWC down to 40 amps because its a continuous load.

Your installer should have known better than to try to send 60 amps(48 amps continuous) through 8 gauge, and properly tighten connections. He also should have been held responsible for the failure, and you shouldn't have expected Tesla to make this better. Its a bad installation, and you should be happy that the electrician didn't burn your house down while you slept.

 

[Tessaract]

But the Wall Connector supports 15A to 100A !!

So you design in a lug that supports the wire sizes required.

 

[mswlogo]

So you design in a lug that supports the wire sizes required.

They did, they decided flat would handle that range. If it was curved for large gauge it would be curved wrong for small gauge.

 

[Tessaract]

They did, they decided flat would handle that range. If it was curved for large gauge it would be curved wrong for small gauge.

Not true. I guess you're not familiar with lugs. I did about 10 seconds of surfing and found this. Good for 00 to 14AWG wire. Buy at Home Depot.

 

[qdeathstar]

should just use ferrules....

 

[Sophias_dad]

should just use ferrules....

Ferrules are great, btw! I'm almost surprised they aren't required.

 

[Tessaract]

Ferrules are great, btw! I'm almost surprised they aren't required.

Ferrules are great. But using them requires an investment in tools most electricians or homeowner don't already have, whereas using tried and proven metal lugs is already common on everyday electrical equipment. I advocate for the solution that is already commonplace elsewhere.

 

[qdeathstar]

Ferrules are great. But using them requires an investment in tools most electricians or homeowner don't already have, whereas using tried and proven metal lugs is already common on everyday electrical equipment. I advocate for the solution that is already commonplace elsewhere.

My ferrule crimper cost 27 bucks. Not exactly a huge investment. It is for smaller gauge wire though and I’m not sure if it would work with 6awg.

 

[brkaus]

My ferrule crimper cost 27 bucks. Not exactly a huge investment. It is for smaller gauge wire though and I’m not sure if it would work with 6awg.

I may have purchased the same crimper. It came in a kit and largest ferrule is 7ga. But looks like there is more space around the crimper so might go bigger. It's saved me so much time seating wires into a buss strip I'm sold!

I did find a reference to a car audio installer that likes to use ferrules on larger wires and doesn't bother with a crimper. He puts them on the wire, holds them with heat shrink that goes just over the edge of the lip on the ferrule. Then uses the mounting point to clamp the ferrule down. Probably an OK approach and they get mangled when connecting anyway and it still gives a good visual that the wire is fully inserted. Not sure though.

 

[Sophias_dad]

I may have purchased the same crimper. It came in a kit and largest ferrule is 7ga. But looks like there is more space around the crimper so might go bigger. It's saved me so much time seating wires into a buss strip I'm sold!

I did find a reference to a car audio installer that likes to use ferrules on larger wires and doesn't bother with a crimper. He puts them on the wire, holds them with heat shrink that goes just over the edge of the lip on the ferrule. Then uses the mounting point to clamp the ferrule down. Probably an OK approach and they get mangled when connecting anyway and it still gives a good visual that the wire is fully inserted. Not sure though.

The crimper I got was 6-10 AWG, in three separate notches. I'd much prefer 2-6 or somesuch, because 10(at least for power) is usually solid.

As far as actual crimping, IIRC I actually crimped each ferrule twice. One would make a decent square with two tips(excess ferrule) hanging parallel off one face of the square, then I'd flip the crimper 180 degrees and go again, which would fold the two tips toward each other and against the one face of the square.

As far as not crimping while using a ferrule, I'm not sure it would be of all that much value, I guess it would keep the individual strands from getting cut, but I don't think it would help much in getting all the strands to participate in the conducting. Why you wouldn't invest in a $25-$75 tool which would get used all the time in the course of your work is baffling, as well.

 

[qdeathstar]

I also agree that is is a mistake not to crimp the ferrule. You don’t know if you are actually making a good connection or just bending over the metal... to plus some audio amps pull lots of current... low voltage high current connections have a higher fire risk that most residential wiring connections, because the faults are harder to detect and the connections tend to be made on the fly.

 

[Tessaract]

I'm not averse to spending some money on a good tool to add to my large collection. I did buy a 40$ ferrule crimper, which came with good reviews, but which did a lousy job of crimping the ferrule. And when crimping 6AWG power conductors for 48 A, unless the crimp is excellent, it would be worse than no ferrule at all. So ya'll may be fooling yourselves into thinking your ferrules are actually helping if your crimps are just so-so. Have you actually crimped 6AWG wire for 48A application?

 

[LaurS]

I have been using the portable EVSE at 40A for 5 months on a 50A breaker with #8 THHN in conduit and 50A outlet. It was an older installation that I only used at 27A before Tesla. Yesterday I bought a Gen2 HPWC and wanted it to install it. To my surprise the #8 does not work with the HPWC. Torquing the screw barely puts any pressure on the wire before bottoming out. Tesla does recommend #6 for 40A. Came looking here and I find this tread, lucky I noticed.

Now I would like some help on sizing the higher amperage circuit. I am stuck at home with no access to full NEC book from work. My conduit will only fit a max of two #4 and one #6. #4 ampacity (or continuous rated current) is 85A at 75C and 95A at 90C. If there is an available continuous 80A rated breaker, then can I use the #4 with the 80A breaker and draw 80A? I do have dual charger. The continuous rated breaker have a note like: "Suitable for continuous operation at 100 percent of rating only if used in a cubicle space 520 by 420 by 200 mm AND when used with 90C wire. The wire shall be sized based on the ampacity of the 75 rated wire".

Any thoughts? I am curious if there are continuous rated breakers for home panels.

Thank you.

 

[Vines]

I didn't find any continuous duty rated breakers for a typical home panel, doubt you will either. Regardless I do not believe the HPWC allows 90C connections, as almost no other equipment does unless its a big lug or designed for a hot environment. Looking at the install manual it specifies 75C wire.

So you cannot use the 90C column unless both ends of the wire are good for 90C

Basically accept that you have 85A continuous to work with and can safely use a 80A breaker to deliver 64A per NEC, or choose to push it.

 

[LaurS]

I kind of expected that there are no continuous duty rated breakers for a typical home panel.

But regarding the HPWC I do not believe that connecting a #4 will be a 90C connection at 80A. #4 is rated 85A continuous at 75C, so it should not even reach 75C at 80A. Actually the wires between the top entry bracket and the HPWC are #4 (with ferrules).

So I could use #4 with a 80A breaker and since is unlikely I would ever charge at 80A for 3 hours (60kWh) I can leave the HPWC set at 80A and set the car to 64A for the location. When I really need the other 16A I can change the setting on the car.

Thank you.

 

[Vines]

No, breakers are rated at 80% of load. Run one at 100% for a long period may develop issues and will likely nuisance trip.

Please don't leave the HPWC at 80A setting then on an 80A breaker. You have no Tesla friends that will ever use your charger?
80A setting on the charger needs to be a 100A breaker in the panel and #3 wire. 64A setting for the 80A breaker. The only thing you gain with your circuit sizing is a fire hazard.

If I was breaking rules and its 3/4" EMT conduit, I'd run the (2) #3 wire for the L1 and L2 and #8 for the EGC, its only 43% full and could be pulled with difficulty, as long a the run isn't too long.

 

[Sophias_dad]

To my surprise the #8 does not work with the HPWC.

I assume that's stranded 8... stick a ferrule on it and it'll tighten down just fine. The HPWC should be connectable down to to 12 gauge non-stranded(I think).

And if you seriously consider taking it to 64 or 80 amps continuous, make sure your panel isn't going to be overloaded. At 80 amps, you are taking HALF of the available output of the 200 amp panel that a recent home would typically be built with. Sure, there's a handful with more, and a much larger number with less(down to 70 or 100, even).

 

[CSFTN]

No, breakers are rated at 80% of load. Run one at 100% for a long period may develop issues and will likely nuisance trip.

Please don't leave the HPWC at 80A setting then on an 80A breaker. You have no Tesla friends that will ever use your charger?
80A setting on the charger needs to be a 100A breaker in the panel and #3 wire. 64A setting for the 80A breaker. The only thing you gain with your circuit sizing is a fire hazard.

If I was breaking rules and its 3/4" EMT conduit, I'd run the (2) #3 wire for the L1 and L2 and #8 for the EGC, its only 43% full and could be pulled with difficulty, as long a the run isn't too long.

I think you mean breakers are rated for the max load, but you should only run 80% of max, continuously. So 100 Amp breakers for 80 amp continuous draw. Another way of saying is multiply your continuous load by 10/8 (or 5/4 or 1.25) to find the correct breaker for the circuit. Not 80% of continuous load, 125% of continuous load is the correct answer.

Yes?

 

[Sophias_dad]

Yes?

Yes.