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My EV car charger / EVSE is a Emporia Classic 48A Smart charger, installed on an exterior wall at the driveway. The J1772 cable is 24 feet long and will drag along the concrete driveway + bushes + grass next to the driveway. I'd like protect the cable from abrasion and wildlife: our neighborhood has rodents, turtles, raccoons, opossum.

I asked Emporia for their recommendation; their reply, emphasis mine:

To protect the cable from the unwanted rodents we could go ahead and use a metal braided sheath! This metal should have no issues with the temperature during the hot summer days.

Metal makes sense for heat dissipation. Unfortunately, metal braided sheath means detaching the J1772 cable because virtually all available sheaths' are too narrow for the large J1772 plug. The braided sheaths appear tricky to slit open and then close up again reliably.

Is this alternative idea below safe?

  1. Wrap the cable with 3M Heavy Duty Aluminum Foil Tape 438. It is an outdoor-rated, thermally conductive, and heat reflecting.

  2. Then, around that, install this Electriduct Stainless Steel Spring Guard Hose Protector. It is also weatherproof.

a rough estimate

My concerns: any electromagnetic risk by having all these metal things wrapped around a 240V @ 48A / 11kW electric cable? I'll also have wrought iron hose guides to keep the cable off the ground wherever possible.

// my current research

  1. I've asked Emporia, but have not heard back for 3 days now.
  2. This DC fast charger appears to uses a metal coil for strain relief. See the far left charger.
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    I wouldn't worry about it. Rubber insulated H07RN-F cable is the goto for construction sites, and it lasts a long time with daily use and a lot more abrasion than your cable will see. I have not even tought about it, and expect the cable to last as long as the car.
    – vidarlo
    Commented Nov 23 at 17:02
  • A braided cable protector, like those available from Techflex "just" slides over the cable. Yes, you need a free end, i.e. no plug, to slip it on but there is no slit involved. Figuring out the precise length needed is a bit of a trick and the ends need to be dressed, e.g. with adhesive lined heatshrink tubing.
    – HABO
    Commented Nov 24 at 3:24
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    Note that a braided cable protector, if it has slack, can easily expand and contract by quite a lot. If they're like the polymer sheaths and metal shields I've seen, they should be able to expand and contract by about a factor of 2 or 3. (Imagine a snake swallowing an egg.)
    – Sophie Swett
    Commented Nov 24 at 5:08

4 Answers 4

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Cut a 24' length of garden hose, split it lengthwise and insert the charge cable. Even the most determined rodents won't gnaw through it and it eliminates the electromagnetic concern.
Wrapping it with tape will keep the cable in place when moving it.

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    Is there any worry regarding changing the heat dissipation ability of the cable by wrapping it in a hose like that?
    – fyrepenguin
    Commented Nov 24 at 16:38
  • @fyrepenguin Well, we'll have to ask the question author or anybody with a similar charger cable whether if gets warm to the touch when running at full throttle.
    – Peter - Reinstate Monica
    Commented Nov 24 at 23:52
  • I've done similar to protect braided hydraulic hoses—take some rubber fuel line, split it lengthwise, insert the hose to be protected, then zip tie along the fuel line every few inches.
    – Huesmann
    Commented Nov 25 at 15:17
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An alternative: If you want to do the braided sheath (metal or polymer, etc), you can easily remove the cable to install the sheath.

I happen to own the same EVSE and took it apart recently to switch it from cord/plug to hardwired.

I've picked up the habit of taking pictures any time I open something and I have a picture of the inside of the EVSE. The vehicle cable has nice crimped ferrules in screw terminals. It should take you about 5 min to get it out.

Interior of Emporia EVSE

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  • One thought - what's the torque spec on the screws? I'd be happy to go with "tight enough" but that may not be safe. Additionally, is it copper or aluminium wiring ?
    – Criggie
    Commented Nov 26 at 9:18
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    Torque spec is unknown, to me at least. "Tight enough" was what I did. There are two stress reliefs on the cable (the metal band clamp and the liquid-tite connector). As for the wires in the vehicle cable, they are stranded copper with ferrules.
    – Chris O
    Commented Nov 26 at 15:32
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    My understanding is that torque spec is the same as that of a breaker - 45 to 50 ft lbs.
    – HoneyDo
    Commented Nov 26 at 19:03
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    @Criggie, I second Chris's comment; if you're relying on the terminal to reject pull-out forces, you're doing it wrong. That is the job of strain relief (a.k.a. stress relief). Ideally, I would want to see some slack on the wires connecting to the terminals, though it looks like that might be challenging here (at least for the AC cable) given the tight space and stiffness of the wires.
    – Matthew
    Commented Nov 26 at 21:17
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    @Matthew Screw terminal torque also affects the size of the contact area between the wire/ferrule and the screw post. Inadequate tightening can result in spot heating. Considering the high current (48A in this case), it is a valid concern.
    – jpa
    Commented Nov 27 at 6:38
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My concerns: any electromagnetic risk by having all these metal things wrapped around a 240V @ 48A / 11kW electric cable?

It is unlikely that wrapping metal around the cable would have any negative effects. The current is returning through the same path so their magnetic fields cancel out. Electric cables are installed into metal conduits all the time.

The metal wrapping could reduce electromagnetic noise emitted to the surroundings, which is a benefit to any nearby amateur radio operators and does not affect the operation of the charger.

You may want to consider grounding the shield at one end or wrapping it in non-conductive covering. This would prevent it getting energized in case you have some unexpected damage to the insulation. I imagine that e.g. accidentally driving over the cable could cut the insulation and be hidden by the shield.

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If you use the foil tape, taping a straight cable will be tough to coil up for storing when not being used and will be ripping apart when handling the cable. Adding the hose protector will make this even harder along with the hose guide. The hose protector won't fit over the plug so you're back to removing the cable. You should think about removing the cable. It shouldn't be a hard job and you can always take it to a repair shop and have them do it. Install the metal braided sheath like the vendor suggested and be done with it. You'll keep the flexibility and ease of use which is important because you'll be using this probably daily.

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  • Using the "roadie wrap" method to coil the cable should help.
    – Andrew Morton
    Commented Nov 24 at 16:04

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