ProspectiveBuyer
Member
Is it safe to use a normal extension cord when charging at work if the 120 volt outlet isn't close enough for the cord to reach?
using extension cords for charging
- Thread starter ProspectiveBuyer
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It is recommended not to, but should be okay given adequate quality extension cord, plugs, and using it uncoiled. Get 10 awg wire to minimize voltage drop, something like: https://www.amazon.com/Coleman-Cable-Outdoor-Extension-Lighted/dp/B00004SQF1 should work.
However, extension cords could increase fire risk. Even my good cord had some burning in the plug after charging my Volt. Might also be wise to use a seal/gasket between the plugs to get a water seal or a cord with like above should seal well at the plug.
Should you use one, towards the end of the charge or after several hours, unplug the EVSE and carefully check temperature of the plug blades. If they are very hot you should discontinue use of the extension cord. Do the same where the cord plugs into the wall. Also check it regularly for damage.
However, extension cords could increase fire risk. Even my good cord had some burning in the plug after charging my Volt. Might also be wise to use a seal/gasket between the plugs to get a water seal or a cord with like above should seal well at the plug.
Should you use one, towards the end of the charge or after several hours, unplug the EVSE and carefully check temperature of the plug blades. If they are very hot you should discontinue use of the extension cord. Do the same where the cord plugs into the wall. Also check it regularly for damage.
Last edited:
Pushmi-Pullyu
Well-Known Member
I don't know, but some of the comments I've read about the risk of fire when using a normal extension cord are pretty alarming. On the other hand, spending hundreds of dollars on a cord that's specifically rated for EV charging seems like a scam.
Aren't there heavy-duty extension cords which can safely handle the continuous draw of the number of amps a L1 charger puts out? Ones which you don't have to spend an arm and a leg for? They say that a circuit rated for EV charging should be rated for 20% more amps than the circuit actually draws. Seems like the same should be true of an extension cord, but that's just my guess... I'm not an electrical engineer.
This is something I'd love to see Consumer Reports make the subject of an article. Let them do something useful for EV owners, instead of just publishing flip-flopping articles about Tesla cars to stir up controversy!
Aren't there heavy-duty extension cords which can safely handle the continuous draw of the number of amps a L1 charger puts out? Ones which you don't have to spend an arm and a leg for? They say that a circuit rated for EV charging should be rated for 20% more amps than the circuit actually draws. Seems like the same should be true of an extension cord, but that's just my guess... I'm not an electrical engineer.
This is something I'd love to see Consumer Reports make the subject of an article. Let them do something useful for EV owners, instead of just publishing flip-flopping articles about Tesla cars to stir up controversy!
And how would they go about doing this?
K8QM
Active Member
My advice would be to use as short as cord as you can, preferably it would be rated at 20 Amps or higher and must be rated for outdoor use.
Make sure the contacts are kept clean!
I'm not sure why people seem to forget that there is just wire (properly sized!) running all the way from your breaker panel to the outlet. When I charge at work there is at least 150 of wire between the outdoor outlet and the breaker panels - adding a 10 or 15 foot extension cord is not going make an appreciable difference.
geo
Make sure the contacts are kept clean!
I'm not sure why people seem to forget that there is just wire (properly sized!) running all the way from your breaker panel to the outlet. When I charge at work there is at least 150 of wire between the outdoor outlet and the breaker panels - adding a 10 or 15 foot extension cord is not going make an appreciable difference.
geo
Don't use extension cords of course. Ignore manufacturers safety recommendations at your peril.
kcsunshine
Active Member
What about those wifi plugs that monitor the usage? I want to see how much kwh I'm using so I can do a real calculation to compare the cost of electricity vs gas. Anyone try that yet?
Sandroad
Well-Known Member
You can get a something like this to record that info. I use one to check usage on many devices.
https://www.amazon.com/P3-P4400-Ele...UTF8&qid=1528893677&sr=8-1&keywords=killowatt
ProspectiveBuyer
Member
Thanks everyone for your feedback.
I wouldn't have a problem with an extension cord if I made it myself using SOOW 12-3 cable, added a twist plug and receptacle and made sure it wasn't subject to physical damage.
The trouble with using extension cords is that folks use one with too small of wire gauge, the cable is too often subject to physical damage, and store bought cables are often poorly made.
The owners manual assumes you are ignorant and should leave electricity to those with training. From a safety point of view, it makes sense.
The trouble with using extension cords is that folks use one with too small of wire gauge, the cable is too often subject to physical damage, and store bought cables are often poorly made.
The owners manual assumes you are ignorant and should leave electricity to those with training. From a safety point of view, it makes sense.
K8QM
Active Member
Yep - everyone lives by rules made for the least common denominator.
Even OSHA allows properly sized extension cords in temporary use.
geo
megreyhair
Active Member
Here is something to keep in mind. The wires inside the cord tends to break near the plugs. Do this check maybe once a week.
1. Let the car charge for like 20 minutes
2. Losely hold the cord in your hand and runn your hand over it and feel for any spot that is warmer than the other.
The warmer spots would mean a few strand of wires inside has broken and cause the resistance at that point to be higher, which cause the temperature to raise. The plastic insulation will melt and cause a fire if the temperature gets too high.
This is similar to what electric company uses to check high voltage transmission lines. ( No they don't have a guy run their hands on the transmission wire. They use a IR scope to check temp. differences. )
If this will become more of a 'permanent' solution for you then you might want to make your own extension using solid wires instead of using the stranded wires inside a extenstion cord. Solid wires won't be as flexible but they are more durable.
1. Let the car charge for like 20 minutes
2. Losely hold the cord in your hand and runn your hand over it and feel for any spot that is warmer than the other.
The warmer spots would mean a few strand of wires inside has broken and cause the resistance at that point to be higher, which cause the temperature to raise. The plastic insulation will melt and cause a fire if the temperature gets too high.
This is similar to what electric company uses to check high voltage transmission lines. ( No they don't have a guy run their hands on the transmission wire. They use a IR scope to check temp. differences. )
If this will become more of a 'permanent' solution for you then you might want to make your own extension using solid wires instead of using the stranded wires inside a extenstion cord. Solid wires won't be as flexible but they are more durable.
KentuckyKen
Well-Known Member
This is a little long since I’m posting for those with no electrical knowledge.
According to the manual and the label, the Clarity EVSE requires a dedicated 15 amp circuit and draws a maximum of 12 Amps.
Here is what you need to know.
Most 15 Amp residential house circuits are wired with 14 gauge wire (12 g for 20 amp) and generally speaking you size the circuit for 80% of the circuit breaker’s size. So here, 80% of 15 is 12 Amps which is the maximum draw of the 120v EVSE or “charger” included with the Clarity. So far so good; just plug into any properly wired 15 or 20 amp outlet in your garage.
But you wish to use an extension cord (manual says no, but it also says things like have an electrician inspect the outlet which nobody does) so here is how I “flaunted” the manual:
First choose an appropriate extension cord for your particular use.
1 Use correct size. For 12 Amps ( lets be safe and size for 15 Amps) and lengths up to 50 ft, the following table tells you that a 12 gauge cord will be plenty and you don't need to waste your money on a bigger 10 g cord as posted above. (For under 25 ft, even a 14 g would be OK, but I only buy 12 g)
Cord Length Device Amperage Rating Good for Use with Minimum Wire Gauge
3 Use correctly and safely. Water and electricity don’t mix, so you have to keep your connections dry. This is why the manual says keep the “brick” 18” off the ground. If plugged in to an outside outlet, the outlet must be protected by a water resistant cover. This is one that protects the outlet from rain when it has something plugged into it. This is different from the outlet cover that came with your house. These can be found at the big box stores.
Both outside and inside the garage (wet car from rain) the connection between the charger and extension cord must also be protected from water. Outside with a cover or inside off the floor.
And remember extension cords are not allowed to go through walls, be continuously flexed, or have doors/windows shut on them.
You should consult an electrician if you are unsure of any of this.
So you can use an extension cord with your 120v charger if you follow the rules. I did for several months before I got my 32 Amp Level 2 EVSE installed.
And BTW, you don’t need a twist plug connection. Even your electric dryer and range don’t need them and they carry much larger loads. Just make sure all connections are fully plugged in and in good working order.
Here is an example of an outdoor outlet cover and cord plug cover:
According to the manual and the label, the Clarity EVSE requires a dedicated 15 amp circuit and draws a maximum of 12 Amps.
Here is what you need to know.
Most 15 Amp residential house circuits are wired with 14 gauge wire (12 g for 20 amp) and generally speaking you size the circuit for 80% of the circuit breaker’s size. So here, 80% of 15 is 12 Amps which is the maximum draw of the 120v EVSE or “charger” included with the Clarity. So far so good; just plug into any properly wired 15 or 20 amp outlet in your garage.
But you wish to use an extension cord (manual says no, but it also says things like have an electrician inspect the outlet which nobody does) so here is how I “flaunted” the manual:
First choose an appropriate extension cord for your particular use.
1 Use correct size. For 12 Amps ( lets be safe and size for 15 Amps) and lengths up to 50 ft, the following table tells you that a 12 gauge cord will be plenty and you don't need to waste your money on a bigger 10 g cord as posted above. (For under 25 ft, even a 14 g would be OK, but I only buy 12 g)
Cord Length Device Amperage Rating Good for Use with Minimum Wire Gauge
- 25 Feet
- 1 – 13 Amps
- Christmas lights
- Work lights
- Portable fans
- Hedge trimmers
- 16 Gauge
(Light Duty)
- 25 Feet
- 14 – 15 Amps
- Lawn mowers
- Power drills
- Table saws
- 14 Gauge
(Medium Duty)
- 25 Feet
- 16 – 20 Amps
- Chain saws
- Circular saws
- Shop vacs
- Air Compressors
- 12 Gauge
(Heavy Duty)
or 10 Gauge
(Extra Heavy Duty)
- 50 Feet
- 1 – 13 Amps
- Christmas lights
- Work lights
- Portable fans
- Hedge trimmers
- 16 Gauge
(Light Duty)
- 50 Feet
- 14 – 15 Amps
- Lawn mowers
- Power drills
- Table saws
- 14 Gauge
(Medium Duty)
- 50 Feet
- 16 – 20 Amps
- Chain saws
- Circular saws
- Shop vacs
- 12 Gauge
(Heavy Duty)
or 10 Gauge
(Extra Heavy Duty)
- 100 Feet
- 1 – 10 Amps
- Christmas lights
- Work lights
- Portable fans
- Hedge trimmers
- 16 Gauge
(Light Duty)
- 100 Feet
- 11 – 13 Amps
- Lawn mowers
- Power drills
- Table saws
- 14 Gauge
(Medium Duty)
- 100 Feet
- 14 – 15 Amps
- Chain saws
- Circular saws
- Shop vacs
- 12 Gauge
(Heavy Duty)
- 100 Feet
- 16 – 20 Amps
3 Use correctly and safely. Water and electricity don’t mix, so you have to keep your connections dry. This is why the manual says keep the “brick” 18” off the ground. If plugged in to an outside outlet, the outlet must be protected by a water resistant cover. This is one that protects the outlet from rain when it has something plugged into it. This is different from the outlet cover that came with your house. These can be found at the big box stores.
Both outside and inside the garage (wet car from rain) the connection between the charger and extension cord must also be protected from water. Outside with a cover or inside off the floor.
And remember extension cords are not allowed to go through walls, be continuously flexed, or have doors/windows shut on them.
You should consult an electrician if you are unsure of any of this.
So you can use an extension cord with your 120v charger if you follow the rules. I did for several months before I got my 32 Amp Level 2 EVSE installed.
And BTW, you don’t need a twist plug connection. Even your electric dryer and range don’t need them and they carry much larger loads. Just make sure all connections are fully plugged in and in good working order.
Here is an example of an outdoor outlet cover and cord plug cover:
That is an uninformed answer.
there was some good content here. this is the same as running any other relatively high amp item....
Checking existing fuse box and outlet along with the other advice on the right cord and keeping it in good working order.....
Great info. I ordered this one:
Century Wire & Cable Pro Power Heavy Duty 25' White Extension Cord https://www.amazon.com/dp/B073FSRBYX/ref=cm_sw_r_cp_apap_uKE7VKtETIU4S
A little expensive but American made and you get to custom print on the cable (that's a thing?).
There's the setup. The power supply is mounted to the wall via the mounting holes... Will have no trouble in winter with the wet floor.
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Pushmi-Pullyu
Well-Known Member
Thanks for a very important safety tip! I've seen it suggested on other forums that you should occasionally check an extension cord do see if it's getting uncomfortably warm, but this is the first time I've seen detailed instructions on how to properly do that.