Model S

Surge protection

edited November -1 in Model S
I charge in the garage with a NEMA 14-50. We lose power a lot, sometimes just for a second. Should I be using a surge protector? Does anybody or is it not needed?


  • edited November -1
    @trixiew, I've read on the forums that the car has plenty of self-protection built in, but I'm still having one of the sacrificial whole-home surge protectors installed.

    The experts here and elsewhere will tell you also that most surge risk comes from things you plug in throughout your house, rather than from outages, and will send you down the road of considering the individual surge protection outlets to replace existing outlets.

    I haven't done that yet, but I have considered it and may ultimately do that. Not just for the car, but the Tesla has been my tipping point on surge protection.

    YMMV, of course.
  • edited November -1
    Do not need it
  • edited November -1
    Thank you for your thoughtful responses. Evanex sells one so I immediately began to fester about it.
  • edited November -1
    I would get one installed on your main panel. It will provide some additional insurance and protect your sensitive electronics including your EVSE and big screen TV.
  • edited November -1
    Experts never say surges come from household appliances. Experts say all appliances already have robust internal protection. You concern is the rare transient that causes damage. That is not reduced voltage during a sag or blackout. Those do not damage electronics. The concern is a rare transient that can overwhelm protection already inside every appliance - and Tesla.

    Any protector that is sacrificial does not provide protection. And is a potential house fire. That is especially of plug in protectors whose hundreds or thousands joules will somehow absorb surges that are hundreds of thousands of joules. Those numbers must exist with every honest recommendation.

    Lightning is maybe 20,000 amps. So a minimal 'whole house' protector is 50,000 amps. Because any protector that fails is ineffective. Then a current for hundreds of thousands of joules does not even enter a house. Then robust protection already inside every appliance and the Tesla is not overwhelmed.

    Protection is always about the path that current takes to earth. Always. Plug-in protectors (or a UPS) that claim to block such currents are bogus and grossly overpriced (have obscene profit margins).

    But even the 'whole house' protector does not do protection. A 'whole house' protector is so effective because it connects low impedance (ie 'less than 10 feet') to what does the protection. Where do hundreds of thousands of joules harmlessly dissipate? In earth. A protector is only as effective as its earth ground. That connection to and quality of earth ground is THE most important part of any protection system. Protectors are only simple and inexpensive devices where 50,000 amps determine its life expectancy.

    Useful replies include the appropriate numbers. Joules, amps, and 'less than 10 feet' are critical to protect household appliances or a Tesla.
  • edited November -1
    An extra layer of surge protection should help, check out the Model S in the video:
  • edited November -1
    The car should be protected at the charger in the car be it single or dual. If damage occurs it should be limited there and not propagated down the line. Although I'm sure Tesla engineers designed the chargers to be robust in this area.
  • edited November -1
    Something like westom says. Surges caused by your own appliances are small at best and protected against. It is the lightning that you care about. If it happens to hit your house, "God forbid", things are going to light up as a Christmas tree whatever you put in. So, you care about the lightning elsewhere.

    In that sense, you need to guard yourself against what could reach your house from the grid. The grid itself is the first layer of protection. It is only capable of delivering some limited energy anyway. Keep in mind, that is still a lot.

    Next thing is your house and what you do there. Mechanical/reactive disconnects that some people I spoke think of are too slow - they would do their job after it is all over - keep in mind that all this takes super small fractions of a second. So this becomes a question of how the energy is channelled in a way that can limit propagation down some paths and "encourage" it to go the other way. Such energy will happily jump across wires so good "insulation" (to use the term loosely) is needed, as well as well as good grounding (this encourages the energy to go that way).

    I have not heard of affordable, yet effective systems. I think their cost goes beyond and effectiveness below what a simple (financial) insurance could do - pay a little and get your entire car replaced should this happen.
  • edited November -1
    I asked Tesla service about this a while back. The response I got:

    "Thank you for contacting Tesla Motors Technical Support. The Model S has protections in place built into the cable as well as the car to avoid any issues with electrical supply. The car is very smart and will protect the battery and charging system from any outside influence.”

    So according to Tesla, surge protection is not needed.
  • edited November -1
    <caption>So according to Tesla, surge protection is not needed.</caption>

    But do they guarantee it? Will they replace anything damaged in the car? Presumably not the UMC or HPWC?

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