EV Charger voltage parameters

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nizak

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Got a call to give a price on installing a 48A 240V EV Charger at a residence.

House has sufficient amperage capacity but voltage is running between 230/233 with AC and Range operating

Is anyone aware of chargers that would go into fault if the voltage dropped to a certain value?

Utility is providing voltage within their parameters but it’s on the low side.

I understand that the rated charging time will be longer with less input voltage but will it damage the charger?

I don’t have any spec yet on the unit just the amperage and voltage.

Thanks
 
I think you’ll be fine, but if you start at 240 no-load and are dropping 7-10V with AC and range, expect another 7-10V drop when charging and those loads also running.

The charger is actually in the car and will operate anywhere between 120 and 240 (nominal). What you are being asked to install is an EVSE, basically a smart switch.
 
Should be no issue for you at all.

I have used several EVSE units at my old shop on 208 VAC (3 phase service) to charge my Chevy Bolt and some other employees Teslas. I am quite sure many commercial units also run on 208.

Like you indicated, it simply takes a bit longer to charge.
 
I think the charger itself on the EV automatically adjusts for the input voltage. The station is what might be voltage sensitive. The early Eaton’s used the neutral for the contactor in order to be universal in the states. They did not make a 208-240 volt rated coil. I assume they have got around that now.
 
hillbilly1 said:
I think the charger itself on the EV automatically adjusts for the input voltage. The station is what might be voltage sensitive. The early Eaton’s used the neutral for the contactor in order to be universal in the states. They did not make a 208-240 volt rated coil. I assume they have got around that now.
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Yes - it’s basically current-controlled. The EVSE tells the car the max current allowed and the car charges at that current (or less if conditions warrant). If the voltage is low, the charge rate in KW is simply lower.

I don’t think any L2 EVSE sold today uses a neutral.
 
retirede said:
I don’t think any L2 EVSE sold today uses a neutral.
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I have installed where they require the neutral to be grounded. Another contractor installed a 480-120/240 transformer for the charger I was installing. He didn't ground the neutral since the charger said 240v on the nameplate, thinking he didn't need a neutral.
While the charger doesn't have a neutral connection, the charger uses some reference to ground and would not boot up without the ground connection at the neutral in the transformer.
 
ScottWJ said:
I have installed where they require the neutral to be grounded. Another contractor installed a 480-120/240 transformer for the charger I was installing. He didn't ground the neutral since the charger said 240v on the nameplate, thinking he didn't need a neutral.
While the charger doesn't have a neutral connection, the charger uses some reference to ground and would not boot up without the ground connection at the neutral in the transformer.
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The installation was wrong regardless of whether the charger needed a neutral and is a serious NEC violation to not ground the the midpoint of a secondary of a transformer like this. It just happens that the charger had enough smarts in it to recognize that it was connected to an ungrounded system. I can only imagine how many other violations are in this setup.
 
ScottWJ said:
I have installed where they require the neutral to be grounded. Another contractor installed a 480-120/240 transformer for the charger I was installing. He didn't ground the neutral since the charger said 240v on the nameplate, thinking he didn't need a neutral.
While the charger doesn't have a neutral connection, the charger uses some reference to ground and would not boot up without the ground connection at the neutral in the transformer.
Click to expand...
It is the groundfault function that all charge controllers require for a ground reference in order to work.
 
hillbilly1 said:
It is the groundfault function that all charge controllers require for a ground reference in order to work.
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I think more precisely, they determine the presence of the EGC based on the voltage L1-G and L2-G.

There’s no reason the GFCI can’t work without a ground reference. It simply measures the difference in current between L1 and L2.
 
retirede said:
I think more precisely, they determine the presence of the EGC based on the voltage L1-G and L2-G.

There’s no reason the GFCI can’t work without a ground reference. It simply measures the difference in current between L1 and L2.
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They have a self test every time they are connected to a vehicle, if that test fails, they will not activate. If the transformer XO is not bonded, like in the previous post, there is no return fault path for the gfci to function, as a leg can go to ground without tripping the gfci. If it is a grounded system, then yes, the gfci will still work even though the egc may not be present at the controller.
 
hillbilly1 said:
They have a self test every time they are connected to a vehicle, if that test fails, they will not activate. If the transformer XO is not bonded, like in the previous post, there is no return fault path for the gfci to function, as a leg can go to ground without tripping the gfci. If it is a grounded system, then yes, the gfci will still work even though the egc may not be present at the controller.
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With the ungrounded secondary, a ground, on say L1, won't trip the GFCI because all that has happened is L1 of the transformer has been grounded, there is no current flowing to ground. Current in L1 and L2 will still match, thus the GFCI is happy that no current is flowing in undesired paths. I am not advocating for an ungrounded connection, just point out why the GFCI would not trip.
 
ScottWJ said:
With the ungrounded secondary, a ground, on say L1, won't trip the GFCI because all that has happened is L1 of the transformer has been grounded, there is no current flowing to ground. Current in L1 and L2 will still match, thus the GFCI is happy that no current is flowing in undesired paths. I am not advocating for an ungrounded connection, just point out why the GFCI would not trip.
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That’s what I just said……..
 
texie said:
I think you folks are missing the issue here. Based on the OP's description this was non compliant from the get go and unsafe.
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Agree…but I was trying to clear up the misconception that a GFCI won’t do its job without an EGC. That’s simply false. The purpose of a GFCI is not to detect ground faults - it’s personnel protection. Otherwise, using a GFCI receptacle to transition an ungrounded 120V circuit to feed NEMA 5-15 receptacles would not be allowed.
 
A GFCI device does not require a GEC to operate, but it does depend on the system being grounded.
 
LarryFine said:
A GFCI device does not require a GEC to operate, but it does depend on the system being grounded.
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Only in the sense that in an ungrounded system the sort of faults it would protect against are less likely.

For example, say you had a generator making a 120/240V system with floating ground (no earthing, no system bonding jumper), and it has two 120V GFCI receptacles on it on different legs. Then if you get across the hot from one receptacle and the neutral from the other receptacle, one or both GFCIs will trip.

Cheers, Wayne
 
LarryFine said:
A GFCI device does not require a GEC to operate, but it does depend on the system being grounded.
Click to expand...

Technically, it does not. It is only sensing the delta in current between the phase conductors. In the example of the original post, if a person were to somehow come into contact with the load side of the EVSE, and the ungrounded center tap of the transformer (or the other phase conductor on the supply side of the EVSE), the GFCI in the EVSE would trip. No grounding required.

In a practical sense, that’s almost physically impossible, but…..

I guess you could say in that case, it’s no longer a GFCI since no “ground” is involved. Maybe that’s why other countries use “RCD”.
 
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