Installing 4-prong charger on 3-wire 240V distribution

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The Nissan EVSE is NOT smart - it pulls 27.5 amps always. So if the door opener doesn't use more than about 3 amps, you could be overloading the circuit but not tripping the breaker. A LAX reading of the electrical code might suggest that you can charge for up to three hours - and no more - on that setup, but it really would be much wiser to just charge at 24 amps (not volts) with an aftermarket EVSE.
 
Correct, no way to limit the charge current on a Leaf, it pulls what it wants, up to a maximum of 27.5a or whatever the maximum of your EVSE is, the OEM Leaf EVSE can pull up to 30a.
Unless something is done not to code, everything else in your garage should be off a 120v breaker and NOT shared with your dryer outlet but still 27.5a on a 30a circuit is asking for trouble, at least for charging for more than an hour or so. I'd suggest purchasing an adjustable EVSE or one maxing out at 24a. 16a L2 EVSEs can be had for under $200, some around $150 but personally if you had a 30a circuit I'd look for a 24a EVSE for quicker charges.
 
jjeff said:
still 27.5a on a 30a circuit is asking for trouble, at least for charging for more than an hour or so.
So, there's two kinds of trouble that could occur:

1) The circuit has a marginal connection in it. When used for a dryer (~23A intermittently) the marginal connection never gets hot enough to cause a problem. But if used for the EVSE (27.5A continuously), the marginal connection will overheat and be a problem.

2) The circuit breaker may nuisance trip. This may occur every time after 2 hours of use, or it may occur rarely when the room temperature is higher than normal and many other loads supplied by the same panel are in use, or it may never occur.

The point of the "80%" rule is solely to avoid #2. That's it. The circuit breaker is the weak link in this regard, and every other part of a 30A circuit is rated for 30A continuously.

Cheers, Wayne
 
The point of the "80%" rule is solely to avoid #2. That's it. The circuit breaker is the weak link in this regard,, and every other part of a 30A circuit is rated for 30A continuously.

Given the additional possibility of a marginal connection overheating - especially in combination with the very real possibility of a defective breaker that won't trip - I think we should at least pretend that #1 is also included. I mentioned a three hour limit on charging just in case the OP plans to disregard our other advice.
 
Absolutely, #1 is a potential issue, that's why I mentioned it. The reopening OP did say "I had a dryer plug installed in my garage that has 240 30 amp on it," which sounds to me like a recent install; hopefully the installer knew what they were doing. I'm also not making any recommendation on what to do, just sharing my understanding of the issue of continuous loads and the NEC.

Cheers, Wayne
 
l6sman said:
I have a sort of similar question. I had a dryer plug installed in my garage that has 240 30 amp on it. I ordered a charger from SplitVolt that is only supposed to charge at 24v. It worked once but then messed up then next time. They're sending me another one. However, I ordered a 14-50 to 10-30 adapter plug from them to try and use with the Nissan charger that came with my 2020 Leaf. According to the Nissan manual, it charges at a continuous 30 amps. When I plugged in using the adapter it seems to work fine and my circuit breaker didn't trip when I turned on overhead lights or ran the garage door opener. Does the Nissan charger have built in intelligence to limit the amps it charges at? Also, I've heard of people limiting how high of amps their Leaf charges at. Can I do that on my 2020, i.e. limit it to lets 24 amps?

Thanks :)

First off; Don't use your setup, its dangerous. You can't run more than 24 "amps" on your dryer connection.

2nd off; I am hoping your testing the garage door opener and whatever else is simply ignorance as there can be NOTHING else sharing that circuit.

3rd off; I use my dryer plug on a splitter with the adapter as well and it works fine one at a time. I use a Clipper Creek 24 amp EVSE.
 
DaveinOlyWA said:
l6sman said:
I have a sort of similar question. I had a dryer plug installed in my garage that has 240 30 amp on it. I ordered a charger from SplitVolt that is only supposed to charge at 24v. It worked once but then messed up then next time. They're sending me another one. However, I ordered a 14-50 to 10-30 adapter plug from them to try and use with the Nissan charger that came with my 2020 Leaf. According to the Nissan manual, it charges at a continuous 30 amps. When I plugged in using the adapter it seems to work fine and my circuit breaker didn't trip when I turned on overhead lights or ran the garage door opener. Does the Nissan charger have built in intelligence to limit the amps it charges at? Also, I've heard of people limiting how high of amps their Leaf charges at. Can I do that on my 2020, i.e. limit it to lets 24 amps?

Thanks :)

First off; Don't use your setup, its dangerous. You can't run more than 24 "amps" on your dryer connection.

2nd off; I am hoping your testing the garage door opener and whatever else is simply ignorance as there can be NOTHING else sharing that circuit.

3rd off; I use my dryer plug on a splitter with the adapter as well and it works fine one at a time. I use a Clipper Creek 24 amp EVSE.

Well, I'm not using a dryer plug per se, I have a dedicated 30 amp circuit breaker and I installed a new dryer plug off of that. The only thing running on that circuit will be my charger. However, I only have 30 amps total going to my garage. When I set I tested the lights and garage door i was checking to see if they plus the Nissan charger were drawing more than 30 amps because I would assume that would trip my breaker but it didn't. That's why I was wondering if the Nissan charger has some intelligence in it so that it doesn't draw more than is available. The manual says it draws a continuous 30 amps. If that was the case then I would've thought that turning on lights or opening my garage door would've trip the circuit. The new SplitVolt charger only draws 24 amps so it should be fine. I am just wondering about the Nissan charger.
 
l6sman said:
DaveinOlyWA said:
l6sman said:
I have a sort of similar question. I had a dryer plug installed in my garage that has 240 30 amp on it. I ordered a charger from SplitVolt that is only supposed to charge at 24v. It worked once but then messed up then next time. They're sending me another one. However, I ordered a 14-50 to 10-30 adapter plug from them to try and use with the Nissan charger that came with my 2020 Leaf. According to the Nissan manual, it charges at a continuous 30 amps. When I plugged in using the adapter it seems to work fine and my circuit breaker didn't trip when I turned on overhead lights or ran the garage door opener. Does the Nissan charger have built in intelligence to limit the amps it charges at? Also, I've heard of people limiting how high of amps their Leaf charges at. Can I do that on my 2020, i.e. limit it to lets 24 amps?

Thanks :)

First off; Don't use your setup, its dangerous. You can't run more than 24 "amps" on your dryer connection.

2nd off; I am hoping your testing the garage door opener and whatever else is simply ignorance as there can be NOTHING else sharing that circuit.

3rd off; I use my dryer plug on a splitter with the adapter as well and it works fine one at a time. I use a Clipper Creek 24 amp EVSE.

Well, I'm not using a dryer plug per se, I have a dedicated 30 amp circuit breaker and I installed a new dryer plug off of that. The only thing running on that circuit will be my charger. However, I only have 30 amps total going to my garage. When I set I tested the lights and garage door i was checking to see if they plus the Nissan charger were drawing more than 30 amps because I would assume that would trip my breaker but it didn't. That's why I was wondering if the Nissan charger has some intelligence in it so that it doesn't draw more than is available. The manual says it draws a continuous 30 amps. If that was the case then I would've thought that turning on lights or opening my garage door would've trip the circuit. The new SplitVolt charger only draws 24 amps so it should be fine. I am just wondering about the Nissan charger.
If the circuit to your garage is only sized for 30 amperes total, then there could be enough voltage drop to cause the Nissan EVSE to fail--this would explain why it worked once if the system voltage was a little higher. The Nissan EVSE will allow the car to pull up to 30 amperes continuous so it needs a 40 or 50 ampere circuit. Also, the Nissan unit will shut down with error lights if it determines the voltage is too low. The Nissan EVSE that came with my 2019 will charge the car fine at my house on nominal 240V, but will not charge the car at my workshop on nominal 208V (typically 212 or 213 volts). It appears to be ready to charge with the EVSE plugged in to the 14-50 receptacle and will appear to start charging when the J1772 connector is plugged in to the car, but will shut down as soon as the car starts drawing current (probably because the voltage drops below its allowable threshold). If you have a 30-ampere circuit, then the "SplitVolt" unit which is rated at 24 amperes should be OK to use.

Other posts in this thread imply that the maximum current the car will draw is 27.5 amperes, but that is not correct. My 2015 would draw 30 amperes when charging from a nominal 208V circuit (typically 212 or 213 volts). The current draw from a nominal 240V circuit would vary with voltage (lower current at higher voltage), but I never saw it above 27.5 because the voltage at my house never got low enough to have the current increase above that level. As an example, the last charge before trading in was 26.6 amperes at 243.3 volts. My 2019 draws a little more current than the 2015: 27.6 amperes at 244.2 volts, 27.0 amperes at 246.1 volts, 26.8 amperes at 250.1 volts, or 28.6 amperes at 236.3 volts. The 2019 will draw a little over 30 amperes when charging from a 208V nominal circuit if the EVSE pilot signal will allow. My Clipper Creek EVSE at my workshop garage allows 40 amperes and I saw 30.4 amperes at 214.3 volts the first time I charged there.
 
l6sman said:
Well, I'm not using a dryer plug per se, I have a dedicated 30 amp circuit breaker and I installed a new dryer plug off of that. The only thing running on that circuit will be my charger. However, I only have 30 amps total going to my garage. When I set I tested the lights and garage door i was checking to see if they plus the Nissan charger were drawing more than 30 amps because I would assume that would trip my breaker but it didn't. That's why I was wondering if the Nissan charger has some intelligence in it so that it doesn't draw more than is available. The manual says it draws a continuous 30 amps. If that was the case then I would've thought that turning on lights or opening my garage door would've trip the circuit. The new SplitVolt charger only draws 24 amps so it should be fine. I am just wondering about the Nissan charger.

You either need to

1-install a 40a or 50a circuit with a 14-50R receptacle to safely use your 240v Nissan ESEV
or
2- buy a ESEV that is limited to 24 amps or less like a Clipper Creek LCS-30P 24 amp L2 ESEV https://store.clippercreek.com/lcs-30p-nema-14-30 or the SplitVolt 24A ESEV https://www.splitvolt.com/product/portable-ev-charger-nema-10-30-24-amp/
 
GerryAZ said:
l6sman said:
DaveinOlyWA said:
First off; Don't use your setup, its dangerous. You can't run more than 24 "amps" on your dryer connection.

2nd off; I am hoping your testing the garage door opener and whatever else is simply ignorance as there can be NOTHING else sharing that circuit.

3rd off; I use my dryer plug on a splitter with the adapter as well and it works fine one at a time. I use a Clipper Creek 24 amp EVSE.

Well, I'm not using a dryer plug per se, I have a dedicated 30 amp circuit breaker and I installed a new dryer plug off of that. The only thing running on that circuit will be my charger. However, I only have 30 amps total going to my garage. When I set I tested the lights and garage door i was checking to see if they plus the Nissan charger were drawing more than 30 amps because I would assume that would trip my breaker but it didn't. That's why I was wondering if the Nissan charger has some intelligence in it so that it doesn't draw more than is available. The manual says it draws a continuous 30 amps. If that was the case then I would've thought that turning on lights or opening my garage door would've trip the circuit. The new SplitVolt charger only draws 24 amps so it should be fine. I am just wondering about the Nissan charger.
If the circuit to your garage is only sized for 30 amperes total, then there could be enough voltage drop to cause the Nissan EVSE to fail--this would explain why it worked once if the system voltage was a little higher. The Nissan EVSE will allow the car to pull up to 30 amperes continuous so it needs a 40 or 50 ampere circuit. Also, the Nissan unit will shut down with error lights if it determines the voltage is too low. The Nissan EVSE that came with my 2019 will charge the car fine at my house on nominal 240V, but will not charge the car at my workshop on nominal 208V (typically 212 or 213 volts). It appears to be ready to charge with the EVSE plugged in to the 14-50 receptacle and will appear to start charging when the J1772 connector is plugged in to the car, but will shut down as soon as the car starts drawing current (probably because the voltage drops below its allowable threshold). If you have a 30-ampere circuit, then the "SplitVolt" unit which is rated at 24 amperes should be OK to use.


OK, thanks for the info. By the way the Nissan charger did not quit working, that's what I assumed it must have some built-in intelligence and be charging at less than 30 amps. The Splitvolt one malfunctioned but it may have been bad from the factory. I have a new Splitvolt one that I am trying out now :)
Other posts in this thread imply that the maximum current the car will draw is 27.5 amperes, but that is not correct. My 2015 would draw 30 amperes when charging from a nominal 208V circuit (typically 212 or 213 volts). The current draw from a nominal 240V circuit would vary with voltage (lower current at higher voltage), but I never saw it above 27.5 because the voltage at my house never got low enough to have the current increase above that level. As an example, the last charge before trading in was 26.6 amperes at 243.3 volts. My 2019 draws a little more current than the 2015: 27.6 amperes at 244.2 volts, 27.0 amperes at 246.1 volts, 26.8 amperes at 250.1 volts, or 28.6 amperes at 236.3 volts. The 2019 will draw a little over 30 amperes when charging from a 208V nominal circuit if the EVSE pilot signal will allow. My Clipper Creek EVSE at my workshop garage allows 40 amperes and I saw 30.4 amperes at 214.3 volts the first time I charged there.
 
So, I have a question relative to this: My power company will sell me power at a reduced rate off-peak if I install a wi-fi EVSE (it has to be a ChargePoint Flex Home, adjustable), and the instructions are clear that it CAN be plugged in if used at the higher amperages (40 or 50) but can not be plugged in, has to be hard wired, if being used at the lower amperages (in my case, 24). This makes no sense to me but someone here will have an idea I am sure....
 
You're right, that doesn't make sense. The only thing I can think of is that the unit comes with a 50A plug and if it is going to be used on a lower rated circuit (eg 30A), you must remove the plug and hard-wire it. I don't know why you couldn't just replace the plug but maybe ChargePoint doesn't want to support someone putting on all kinds of various plugs on their units.

Edit to add: or maybe it only has a UL rating for those configurations.
 
LeftieBiker said:
I just woke up, but I suspect they don't want you to just unplug it and sell it, after getting the lower rate. Can they track it themselves?

I am buying the unit myself since the program came along after I bought the Leaf, so re-selling is not the issue. As Goldbrick points out, the plug-in cable that comes with it is larger than needed for the lower charging rates, but I can not see this as a safety issue (unless someone sees the larger cable and plug and decides to up the amperage without checking the rest of the system?). I live thousands of feet off into the woods and no one is ever going to come along and do that......

As for the electricity tracking, yes they will have wifi access to the EVSE unit I suppose to verify that only the power they consider off-peak gets the lower rate- since I only charge between 12 and 4 AM this should be pretty safe.
 
l6sman said:
GerryAZ said:
l6sman said:
Well, I'm not using a dryer plug per se, I have a dedicated 30 amp circuit breaker and I installed a new dryer plug off of that. The only thing running on that circuit will be my charger. However, I only have 30 amps total going to my garage. When I set I tested the lights and garage door i was checking to see if they plus the Nissan charger were drawing more than 30 amps because I would assume that would trip my breaker but it didn't. That's why I was wondering if the Nissan charger has some intelligence in it so that it doesn't draw more than is available. The manual says it draws a continuous 30 amps. If that was the case then I would've thought that turning on lights or opening my garage door would've trip the circuit. The new SplitVolt charger only draws 24 amps so it should be fine. I am just wondering about the Nissan charger.
If the circuit to your garage is only sized for 30 amperes total, then there could be enough voltage drop to cause the Nissan EVSE to fail--this would explain why it worked once if the system voltage was a little higher. The Nissan EVSE will allow the car to pull up to 30 amperes continuous so it needs a 40 or 50 ampere circuit. Also, the Nissan unit will shut down with error lights if it determines the voltage is too low. The Nissan EVSE that came with my 2019 will charge the car fine at my house on nominal 240V, but will not charge the car at my workshop on nominal 208V (typically 212 or 213 volts). It appears to be ready to charge with the EVSE plugged in to the 14-50 receptacle and will appear to start charging when the J1772 connector is plugged in to the car, but will shut down as soon as the car starts drawing current (probably because the voltage drops below its allowable threshold). If you have a 30-ampere circuit, then the "SplitVolt" unit which is rated at 24 amperes should be OK to use.


OK, thanks for the info. By the way the Nissan charger did not quit working, that's what I assumed it must have some built-in intelligence and be charging at less than 30 amps. The Splitvolt one malfunctioned but it may have been bad from the factory. I have a new Splitvolt one that I am trying out now :)
Other posts in this thread imply that the maximum current the car will draw is 27.5 amperes, but that is not correct. My 2015 would draw 30 amperes when charging from a nominal 208V circuit (typically 212 or 213 volts). The current draw from a nominal 240V circuit would vary with voltage (lower current at higher voltage), but I never saw it above 27.5 because the voltage at my house never got low enough to have the current increase above that level. As an example, the last charge before trading in was 26.6 amperes at 243.3 volts. My 2019 draws a little more current than the 2015: 27.6 amperes at 244.2 volts, 27.0 amperes at 246.1 volts, 26.8 amperes at 250.1 volts, or 28.6 amperes at 236.3 volts. The 2019 will draw a little over 30 amperes when charging from a 208V nominal circuit if the EVSE pilot signal will allow. My Clipper Creek EVSE at my workshop garage allows 40 amperes and I saw 30.4 amperes at 214.3 volts the first time I charged there.

Based on the conversations above and the fact that the Nissan charger didn't fail on a 30amp breaker, does anyone know whether the Nissan charger has built-in intelligence that allows it to charge at a lesser rate? I'm thinking it may since the breaker didn't trip. I know it charges faster than the SplitVolt charger.
 
l6sman said:
Based on the conversations above and the fact that the Nissan charger didn't fail on a 30amp breaker, does anyone know whether the Nissan charger has built-in intelligence that allows it to charge at a lesser rate? I'm thinking it may since the breaker didn't trip.
No.

A properly functioning 30 amp breaker may trip at 27 amps continuous after an hour. Or it may never trip at 35 amps continuous. The variation depends on manufacturing tolerances and the ambient temperature of the breaker (which in turn depends on how other breakers in the enclosure are loaded).

This variation in breaker trip characteristics is the reason for the 80% continuous load limit in the NEC.

Cheers, Wayne
 
wwhitney said:
l6sman said:
Based on the conversations above and the fact that the Nissan charger didn't fail on a 30amp breaker, does anyone know whether the Nissan charger has built-in intelligence that allows it to charge at a lesser rate? I'm thinking it may since the breaker didn't trip.
No.

A properly functioning 30 amp breaker may trip at 27 amps continuous after an hour. Or it may never trip at 35 amps continuous. The variation depends on manufacturing tolerances and the ambient temperature of the breaker (which in turn depends on how other breakers in the enclosure are loaded).

This variation in breaker trip characteristics is the reason for the 80% continuous load limit in the NEC.

Cheers, Wayne

OK thanks. Then does it hurt using the original Nissan charger since it seemed to work fine? There is no way to tell the Leaf to only charge at 24 amps instead of 30 amps is there?
 
It doesn't "hurt" the charging cable, but there is a "risk" involved in using it this way, especially for more than a couple of hours. You will also be violating the National Electrical Code, and that may prevent an insurance payout if there is a fire.
 
l6sman said:
OK thanks. Then does it hurt using the original Nissan charger since it seemed to work fine?
To my knowledge, the only hazard the NEC is seeking to avoid with the requirement of a maximum 80% continuous load on a breaker is the hazard of repeated nuisance tripping. This is a real hazard, as if the user gets in the habit of just resetting the breaker, then the breaker will wear, and the user will not be able to tell if it starts tripping for some other reason.

Also, I believe you mentioned that your garage is fed by a 30A 120V/240V circuit, and that it has other loads. Even if your breaker holds with the continuous 27.5A load of the Nissan Leaf alone, there is a significant probability of it tripping when other loads happen to come on. I.e. just because you tried the garage door opener once doesn't mean that there isn't a 1% or 5% chance of it tripping each time you use the garage door opener. Sticking with the 24A continuous EVSE would give you more headroom.

Lastly, I don't know what pilot signal the Nissan EVSE uses. If it advertises 30A or 32A, and you ever plug in another EV that can charge at that rate, you're quite likely to trip the 30A breaker.

So for those reasons, it is more prudent to use the 24A continuous EVSE, rather than the Nissan EVSE.

Cheers, Wayne

PS For those less familiar with the NEC, the requirement for continuous loads is written in terms of providing conductors with an ampacity (amp capacity) of 125% of the continuous load. Which at first glance suggests that the conductors themselves are in need of upsizing for continuous load. But basically every instance of this requirement has an exception stating that if the circuit is supplied by a "100% rated" breaker, then the conductors may be sized at 100% of the continuous load. A "100% rated" breaker consists of a single breaker in its own enclosure (to avoid heat buildup from other breakers) that has been tested to hold at a continuous current matching its rating. [And they basically don't exist smaller than 100A.] This shows that the continuous load requirements are due to the limitations of standard breakers, and nothing else.
 
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