Question HPWC load sharing question

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R H

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#1
I know it’s possible to load share up to 4 HPWC’s on 1 circuit. I also know it’s possible to create a NEMA 14-50 pigtail and connect a HPWC to it and just set the amp limit under 50. I’m wondering if it’s possible to do both.. basically load share 2 HPWCs hooked up to a single NEMA 14-50 and set to a max amperage of under 50? Please don’t respond with ‘why would you want to do that?’, ‘That’s a terrible idea’, ‘You should do this way instead’ etc etc. I have my reasons. I’d just appreciate knowing if this is a possible workable setup.

Thanks a lot for you help.
 

MelindaV

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#2
the WC (Tesla dropped the HP in HPWC around 2016, before you could daisy chain them) doesn't know where the power is coming from. so there should be no reason it could tell the difference if the main unit was hard wired or plugged into a 14-50.
 

GDN

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#4
Agree - it doesn't know or care where the power comes from. If it is shared, just make sure their internal settings are correct telling it what power it has and add the communication wire, the WC should handle the rest.
 

R H

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#7
thanks garsh. good to know. I thought they somehow communicated over the power wires. Now that i’ve actually seen the manual, It’s pretty clearly answers all my question about that.
Some background info for anyone interested. When I had my electrician install my NEMA 14-50 i elected to go with a smaller less expensive conduit from my circuit breaker box that won’t easily be upgraded to 100 amps. it was cheaper and easier to put the 14-50 receptacle at the inside end of the garage, which means i pretty much have to back in (which is what I always did anyway) . I’m now hoping to get a second tesla (which I never imagined doing when i had it installed). wife is not going to want to back in. I really don’t want to deal with an electrician gain if I can avoid it. I think the biggest challenge here will be figuring out how to run a large conduit with both high voltage and low voltage from one end of the garage to the other. I don’t foresee any problems with speed of charging in my current situation with power sharing of 2 WCs and a max of 40 Amps.
I changed my mind, feel free to offer any suggestions that contradict my current (no pun intended) plan.
 

garsh

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#8
I changed my mind, feel free to offer any suggestions that contradict my current (no pun intended) plan.
I think your reasons for sticking with 40 amp charging (80% of 50amp) are sound. The only suggestion I would make is to not put a NEMA 14-50 pigtail on the wall connector. Remove the 14-50 outlet altogether, and wire the circuit directly to the wall connectors.
 

iChris93

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#9
I think the biggest challenge here will be figuring out how to run a large conduit with both high voltage and low voltage from one end of the garage to the other.
Check your local code, but I think most places do not allow for high and low voltage lines to be in the same conduit.
 

TirianW

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#11
You will want to check local code, but usually the low voltage cable does not need to be in a conduit. If you want to put it in one you can, but it is not required it most jurisdictions. And like @iChris93 said, it needs to be a separate conduit if you run it in a conduit. While I don't have two Tesla Wall Chargers, I did run low voltage cable to all my Seimens VersaChargers so I can remotely turn them on and off - the low voltage cable was not put in a conduit, the high voltage cable was.
 

F0ZZ

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#12
Will Cat6 suffice for the low voltage cable? I’m in the middle of a garage reno and I want to run cable to make life easier when we purchase our second Tesla.
 

garsh

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#13
Will Cat6 suffice for the low voltage cable? I’m in the middle of a garage reno and I want to run cable to make life easier when we purchase our second Tesla.
The manual recommends a shielded cable, but I think a twisted pair like cat6 would be fine.
 

F0ZZ

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#16
I don’t think mine is shielded, no foil inside. But you can buy it that way if you have the foresight. I bought too much when I ran wire for my home automation system. I’m looking for jobs to do with it.
 

oshw

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#17
It's a low speed Rd-485/422 network for load sharing. I don't think you'll need shielding.

White shielding on a cable like this, where wwould the shield terminate to? Does the manual day anything about shield termination?
 

TirianW

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#18
I thought CAT6 was twisted and shielded.
It can be, but it is not required to be. There are shielded and unshielded versions of CAT5, CAT6, and CAT6a*. In general, shielded cable is recommended if it will be run parallel and adjacent to power lines for any distance, you would want to connect the drain wire from the shield to ground at one end (but not both ends). For short runs, runs with spacing between the data cables and power lines, or runs where the data and power lines are not parallel then shielding is not required.


* I understand that all CAT7 cable is shielded, but I have not worked with it; also I am not aware of any shielded CAT3 cable.