Extra long charging cord?

There was talk that the Owners Manual says not to use extension cords. However, the wires from your House Power Panel Box to an outlet are no more than Extension wires.

Home Depot has 25', 50' and 100' cords.
12 gauge wire with 3 wires (hot, neutral and ground), or 12/3 is good for 15 amps at 125 vac.

10 gauge, 3 wire or 10/3 is also listed for 15 amps at 125 vac.
I thought it would be rated more, say for 20 amps.

Though 12/3 is all you need, 10/3 is more heavy duty, thus more $$.

 

True. And your home was presumably wired to code with wire size large enough to prevent too much voltage drop to the most distant outlet, and too much heat buildup in the wiring, etc. Adding additional length with extension cords beyond this could result in too much voltage drop. Toyota's position is the "safe" one assuming worst-case home wiring and because they can't assume everyone would use a heavy enough extension cord. But in some cases, a limited length heavy duty extension cord might work, especially if your charging outlet is near the main service entrance to your house.

Heat buildup could also be a concern, so you should check the cord's rating. Sometimes, the plug can heat up more than the wire. The plug (and outlet) can be a weak part of the path, with oxidation of the contacts, or small contact points in the cord between the plug and the wire. Heat buildup can be a concern with EV charging, since recharging draws a lot of current for a long period of time.

There are calculators that will give you an idea how much voltage drop an extension cord will produce (and the same for your home's wiring, if you can estimate the length of that). Here's one: Voltage Drop Calculator ("1/2 circuit length" is the cord length, because the total circuit includes the path out through one wire in the cord, and return path back through the other wire).

If using an extension cord, I'd definitely go with 12 gauge or heavier (many cords sold are lighter, often 16 gauge, or sometimes 14). And for the first use, I'd check for the plugs getting hot to make sure your cord is handling the load safely.

 

Yellow Jacket makes good extension cords. Expect to pay at a minimum $1.00/ft. If you go 50', I suggest 10/3.

One of you hard core electrician types please correct me: the 15 amp rating for heavy gauge extension cords relates to the rating of a 3 prong 120V outlet (NEMA), rather than the length and gauge of the wire? 25' generator cords of 10 gauge wire have 30 amp ratings, for example.

 

The main reason they say not to use extension cords is because extension cords defeat the safety circuits in the charge cord box. In addition, many people think all extension cords are equal and will use any old crappy thin-gauge cord. Those may work fine for your LED Christmas lights and light gardening tools, but not for continuous heavy load.

The orange Rigid cords at Home Depot are of good quality. Good quality, clear connectors so you can see that the plugs have a good connection to the wire. The cord is very flexible and easy to work with. And the socket is lighted with a little neon bulb inside which is a nice feature.

The red cord linked to above is crap. Poor quality connectors and not very flexible wire. Spend the extra couple bucks on the orange cord.

The main reason the 10 ga cord is rated 15A like the other cords is that it's longer and still only has NEMA 5-15 plug/socket.

I wouldn't bother with 10 ga unless going 100 ft. I wouldn't use anything less than 12 ga except in an emergency and with careful monitoring.

Always use the shortest cord possible and do not coil the excess cord to avoid heat build up. I would prefer to have 2 high quality 25' cords rather than 1 50'.

And as Gary in NY suggests, check on the plugs to make sure they're not overheating - those are the most likely spots to cause trouble.

 

The usual rule of thumb is 14 Gauge is used for 15 Amps, 12 Gauge for 20 Amps, and 10 Gauge for 30 Amps, but for longer distances, larger wire sizes may be needed.

The 15 Amp rating on a 12 Gauge cord probably does come from the plug type. There actually are different plug types for 20 Amps vs. 15, and I think the cord can't carry a 20 Amp rating if it uses a 15 Amp plug. We practically never see 20 amp plugs for household use, but you can find what they look like here: Nema Plug and Receptacle configurations. The 2 blades are not parallel. You may have some 20 Amp outlets in your house, because those accept both 15 and 20 Amp plugs, but chances are, you've never plugged a 20 amp plug into one.

 

I don't think the wire gauge is the problem. The problem is the extra connections. It creates resistance and gets hot. I'm using 25' 12/3 extension as my charging cable. No J1772 for aftermarket plugin. The wire near the plugs get warm to the touch while the wires 3' from the plug stays cool. The wire that connects to the prong creates resistance. The prongs connecting the receptacle creates resistance. Receptacle connecting to the wire also creates resistance. The only safe extension cable is to locate a charge cable that already has the long cord.
You can try buying an extra charger, open it up and replace the cord with 50' 10/3 extension cord.

 

Anyone buy and using a ≤12 gauge extension cord and tested it to make sure no significant change in amperage or voltage? I know Toyota says not to use extension cords, but I think they are worried that someone will use a long 14-16 gauge extension cords and ruin the battery/electric system or start a fire by overheating.

 

I went to Home Depot and found two 25 ft 12 gauge extension cords. One was labelled "Heavy Duty". It was about $10 more ($35). That's the one I got. I checked the cable and connectors while charging and they are not getting warm. The car says I am charging at 1.0 to 1.1 amps. I like the fact that the the connectors are clear and there is a neon light in the female end to show that it has power.

 

I got the Rigid 12/3 cord rated 15 amps from Home Depot - $35. Works great. Note that the cord from the charge cord box to the J1772 plug is 12ga but the cord from the charge cord box to the wall plug is 14ga... 12ga cord should be fine.

 

Toyota also warns that the extension cord does not contain GFCI on pf. 79 of the Owner's Manual.

 

At work, I am forced to use an extension cord because there are only a few outlets within the range of the charge cable Toyota shipped with the car (and those parking spaces are usually filled by the time I get to work). I use a 25 ft, 12 gauge extension cable and have not had any problems.

 

I use that same cord at work out my window, until the building owner allows me to install an outside outlet.

My Kill A Watt shows the same 11.6 -11.7 amps, as it does at home, where I plug into my 20 amp outlet wired with 10 gauge wire to the Breaker Panel 50' away.

 

...and how long is that cord j ?

 

Probably a RV extension cord would be perfect, they are larger guage so should not increase ohms to any extent. You may have to fit standard 120V plugs on.

 

25ft... Costco has a 12ga, 15A 100ft cord for $40 as well, but that's too long and heavy for me. Might also get a shorter one just to allow the box to sit on the ground when I don't really need an extension.

 

any one seen a posted picture of the non business end of the evse? i'm installing the outlet in my garage and trying to decide on the height. is there anything on that end that need to be at eye level? thanks!

 

You mean to say that one end is inert? I happen to have two double outlets, one by the HVAC, and the other right on the inside wall in the middle of my workbench. The height is slightly above my waist, which seems perfect, since the non-inert end plugs into the Prius just a bit lower. I say perfect because, everyone knows electrons like water flow downhill !!!
:cheer2: But, you were referring to a evse, what is that, it must stand for something? Are you hooking up 220V ?
I have lost track of the # of times I have charged my non-existent PIP, I'm getting infinite MPG and at no cost.

 

LOL, should i continue with the funny business? seriously tho, the only pic i can find of the charging cord that comes with the pip (for 110v) shows a small box with some light codes and about 12-18" of cord with plug. if this is the case, i think it would be best to have the outlet high on the wall to make it easy to read the codes on the box. i can put it at any height. the wire comes in about a foot off the floor from the basement which seems way too low. okay, have at it!