Using a dryer circuit for an EVSE

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fhammond

Active member
Joined
May 17, 2013
Messages
25
Location
Oakland, CA
Installing an EVSE has turned out to be more complicated than I'd hoped. My house is old and the entire external fusebox would have to be replaced to add another 30 amp circuit. My next option was to replace my electric dryer with a gas dryer and use the circuit for the EVSE. However, I've discovered that gas dryers still need between 10 and 15 amps and it's doubtful if I've got that spare on another circuit. (And gas dryers need external ducting; more expense.)

So I'm coming round to the idea of having a switch on the dryer circuit: one position for the dryer and one for the EVSE, preventing both from being used at once. It's a little inconvenient but not too bad.

My question is this: Is there a way to test what current the dryer circuit can deliver? It's got a 30 amp fuse but I'd like to know if it can deliver a full 30 amps before I pick an EVSE. If it can't, I'll find a model that draws 16 or 20 amps. There's already a few EVSEs I can't use because they required 40 amps.

Any suggestions would be appreciated. Thanks!
 
I am using dryer plug but have old LEAF so charging rate not an issue for me. I did not remove dryer, just swap plugs back and forth which is a pain somewhat but no better or worse than any of the other charging options I am using. I also installed regular plug at Sis's house which is uncovered and outside. have to haul EVSE out of the trunk to plug in but am there frequently enough and the charge opps really comes in handy.
 
fhammond said:
My question is this: Is there a way to test what current the dryer circuit can deliver? It's got a 30 amp fuse but I'd like to know if it can deliver a full 30 amps before I pick an EVSE. If it can't, I'll find a model that draws 16 or 20 amps. There's already a few EVSEs I can't use because they required 40 amps.
Click to expand...
Actually, there are a lot of EVSEs you can't use, most of them, in fact. EV charging is a continuous load, and is not allowed to pull more than 80% of the circuit rating. So anything greater than a 24A load on your circuit is illegal and potentially dangerous.

I expect you will find a 16A EVSE will be quite adequate for your needs. It can charge the car from empty to 100% in seven hours, i.e. easily, overnight. If you want something a bit faster, there are a few 20A EVSEs. The Clipper Creek LCS-25 is one. (They call it a "25" because Clipper Creek rates their EVSEs by the size of the circuit it needs to be connected to, not by the power it draws.) Phil, at evseupgrade.com will do a beautiful job of upgrading the 120v EVSE that comes with your car to a very flexible dual-voltage EVSE which runs at a selectable current up to 20A at 240v. He has, literally, thousands of satisfied customers who post on this board.

I'm not suggesting that the 6 kW charger you are presumably getting on your 2013 LEAF is a silly gimmick. You will find it very valuable any time you need to charge away from home (unless you can find an even better Quick Charge). It's just that for most people the primary advantage of 6 kW over 3.3 kW is for charging on the road, not at home.

Ray
 
Go to Lowes, purchase a dryer pigtail, two receptacles, and a plastic junction box to make a splitter. If you really mean fuse, and not circuit breaker, then you probably need NEMA 10-30 components. Otherwise, probably 14-30.

I have done that with my 14-50 electric stove outlet.
 
planet4ever said:
Actually, there are a lot of EVSEs you can't use, most of them, in fact. EV charging is a continuous load, and is not allowed to pull more than 80% of the circuit rating. So anything greater than a 24A load on your circuit is illegal and potentially dangerous.

I expect you will find a 16A EVSE will be quite adequate for your needs. It can charge the car from empty to 100% in seven hours, i.e. easily, overnight. If you want something a bit faster, there are a few 20A EVSEs. The Clipper Creek LCS-25 is one. (They call it a "25" because Clipper Creek rates their EVSEs by the size of the circuit it needs to be connected to, not by the power it draws.) Phil, at evseupgrade.com will do a beautiful job of upgrading the 120v EVSE that comes with your car to a very flexible dual-voltage EVSE which runs at a selectable current up to 20A at 240v. He has, literally, thousands of satisfied customers who post on this board.

I'm not suggesting that the 6 kW charger you are presumably getting on your 2013 LEAF is a silly gimmick. You will find it very valuable any time you need to charge away from home (unless you can find an even better Quick Charge). It's just that for most people the primary advantage of 6 kW over 3.3 kW is for charging on the road, not at home.

Ray
Click to expand...

Ray, this is very useful information! Thanks very much.

Here's my dilemma: if I've got a 30A circuit, how would I connect a 16A or 20A EVSE to it? Don't I then run the risk of overheating the unit? It seems I would need some sort of transformer to take the 240V/30A circuit and turn it into a circuit suitable for the EVSE.

Are there 30A EVSEs that actually draw less than 30A? I assuming the answer is "no" or "yes, but only a little less current" since the whole point of the EVSE is to get as much power into the car's charger as possible.

Regards,
Fergus
 
ClipperCreek has a 20a evse. (LCS-25) Made for hardwire but you should be able to add a cord and plug it right in. Hardwire it with a switch if you are inclined.
 
fhammond said:
Here's my dilemma: if I've got a 30A circuit, how would I connect a 16A or 20A EVSE to it? Don't I then run the risk of overheating the unit? It seems I would need some sort of transformer to take the 240V/30A circuit and turn it into a circuit suitable for the EVSE.

Are there 30A EVSEs that actually draw less than 30A? I assuming the answer is "no" or "yes, but only a little less current" since the whole point of the EVSE is to get as much power into the car's charger as possible.

Regards,
Fergus
Click to expand...

That's not how it works at all. A 16A or 20A EVSE will only draw that much current MAX. Your dryer doesn't draw 30 amps continuous, if it did, it might sometimes blow your fuse (or breaker). In no case would you want or need a transformer, the car can accept 240 volts just fine, it will draw as much current (amps) as the EVSE tells it to take. The EVSE actually communicates with the charger in the car, and the charger will operate at the current (amps) that the EVSE allows, up to the chargers max.


You should provide us more information. Can you open your "fuse" box and take a photo of it? Don't touch anything inside it, just open the door and take a photo and post it in this thread. That would be helpful!
 
kentuckyleaf said:
fhammond said:
Here's my dilemma: if I've got a 30A circuit, how would I connect a 16A or 20A EVSE to it? Don't I then run the risk of overheating the unit? It seems I would need some sort of transformer to take the 240V/30A circuit and turn it into a circuit suitable for the EVSE.

Are there 30A EVSEs that actually draw less than 30A? I assuming the answer is "no" or "yes, but only a little less current" since the whole point of the EVSE is to get as much power into the car's charger as possible.

Regards,
Fergus
Click to expand...

That's not how it works at all.
Click to expand...

Which problem are you referring to? I've got two dilemmas:

1. If I get a 16 or 20 A EVSE, how can it be connected to a 30A circuit? I don't think it can without a transformer
2. Can a 30A EVSE be safely connected to a dedicated 30A circuit or, based on Ray's comment about the 80% load recommendation, should a 30A EVSE be connected to a 40A or larger circuit?

I will post a picture of the fuse box when I get more time but it's not pretty. A 30A circuit goes directly to the dyer and there's another connection to a single, fused sub-panel inside. Neither has any space. Two different electricians have given me a quote for a fix and neither was cheap. The guy I'm working with now thinks the switch on the dryer circuit is the best choice.
 
fhammond said:
1. If I get a 16 or 20 A EVSE, how can it be connected to a 30A circuit? I don't think it can without a transformer
2. Can a 30A EVSE be safely connected to a dedicated 30A circuit or, based on Ray's comment about the 80% load recommendation, should a 30A EVSE be connected to a 40A or larger circuit?
Click to expand...
Up to 24a evse can be connected direct to the 30a circuit.

30a evse needs a 40a circuit to meet code.
 
smkettner said:
fhammond said:
1. If I get a 16 or 20 A EVSE, how can it be connected to a 30A circuit? I don't think it can without a transformer
2. Can a 30A EVSE be safely connected to a dedicated 30A circuit or, based on Ray's comment about the 80% load recommendation, should a 30A EVSE be connected to a 40A or larger circuit?
Click to expand...
Up to 24a evse can be connected direct to the 30a circuit.

30a evse needs a 40a circuit to meet code.
Click to expand...

I don't understand how a 24A EVSE can be connected to a 30A circuit. I'm looking at the Clipper Creek manual (http://goo.gl/peZHP" onclick="window.open(this.href);return false;) and on page 10 it says that their LCS-25 needs a 25A circuit. My issue is that I can only easily use what I've got: a 240v/30A circuit. I think that's going to prevent me from using a 24A EVSE.

But I'm new to this and could be completely wrong.
 
fhammond said:
smkettner said:
fhammond said:
1. If I get a 16 or 20 A EVSE, how can it be connected to a 30A circuit? I don't think it can without a transformer
2. Can a 30A EVSE be safely connected to a dedicated 30A circuit or, based on Ray's comment about the 80% load recommendation, should a 30A EVSE be connected to a 40A or larger circuit?
Click to expand...
Up to 24a evse can be connected direct to the 30a circuit.

30a evse needs a 40a circuit to meet code.
Click to expand...

I don't understand how a 24A EVSE can be connected to a 30A circuit. I'm looking at the Clipper Creek manual (http://goo.gl/peZHP" onclick="window.open(this.href);return false;) and on page 10 it says that their LCS-25 needs a 25A circuit. My issue is that I can only easily use what I've got: a 240v/30A circuit. I think that's going to prevent me from using a 24A EVSE.

But I'm new to this and could be completely wrong.
Click to expand...

u r completely wrong. a transformer would be needed for differences in Voltage, not current. a 25A circuit requirement means 25A OR GREATER
 
fhammond said:
I don't understand how a 24A EVSE can be connected to a 30A circuit. I'm looking at the Clipper Creek manual (http://goo.gl/peZHP" onclick="window.open(this.href);return false;) and on page 10 it says that their LCS-25 needs a 25A circuit. My issue is that I can only easily use what I've got: a 240v/30A circuit. I think that's going to prevent me from using a 24A EVSE.

But I'm new to this and could be completely wrong.
Click to expand...
You are completely wrong about this. :D (but that's OK). You can always plug a lower amperage appliance into a socket/circuit that supplies higher amperage. That's why you can plug in a lamp that draws 120v 0.5a into your 120v 15a wall socket without problems. There is absolutely no reason you shouldn't plug a 16a or 20a EVSE into your 30a circuit. You just need the proper plug adapter. In your shoes, I would contact EVSEUpgrade.com. They have sold hundreds of their upgrades to people who are doing exactly what you are. They are very friendly and knowledgeable, and will tell you exactly what you need to run one of their upgrades on your dryer circuit successfully.
 
fhammond said:
smkettner said:
fhammond said:
1. If I get a 16 or 20 A EVSE, how can it be connected to a 30A circuit? I don't think it can without a transformer
2. Can a 30A EVSE be safely connected to a dedicated 30A circuit or, based on Ray's comment about the 80% load recommendation, should a 30A EVSE be connected to a 40A or larger circuit?
Click to expand...
Up to 24a evse can be connected direct to the 30a circuit.

30a evse needs a 40a circuit to meet code.
Click to expand...

I don't understand how a 24A EVSE can be connected to a 30A circuit. I'm looking at the Clipper Creek manual (http://goo.gl/peZHP" onclick="window.open(this.href);return false;) and on page 10 it says that their LCS-25 needs a 25A circuit. My issue is that I can only easily use what I've got: a 240v/30A circuit. I think that's going to prevent me from using a 24A EVSE.

But I'm new to this and could be completely wrong.
Click to expand...

How does that 1 amp lamp work plugged into a 15a outlet. ;)

Yes LCS-25 needs a minimum 25a circuit so 30a circuit is fine, 40a is fine, 50a is fine.
 
fhammond said:
I don't understand how a 24A EVSE can be connected to a 30A circuit.
Click to expand...

Think of amperage as the balance in a bank account. You can draw (in this case, electricity vs. money) up to, but not beyond, that "balance." No, there is no "overdraft" fund that can cover for you.

And just like many bank accounts require a minimum balance or else fees are imposed, with any electrical circuit you should not draw more than 80% of its rated load, or "balance", continuously over a period of time, or else you risk a fire. So a circuit rated for "up to" 30 amps can safely draw up to 80% of that, or 24 amps.

Hopefully this will clear up your confusion about amperage.
 
Whatever plan you end up deciding on I would strongly urge you to have an electrician help you implement it. There isn't any way that all of us on this forum are going to be able to ensure that all the considerations needed in your home are accounted for to ensure that you are able to charge safely.

As suggested the EVSEUpgrade is a very cost effective choice combined with your existing dryer circuit but this still needs to be checked out by an electrician and they should help you with any modifications needed to make charging more convenient.
 
QueenBee said:
Whatever plan you end up deciding on I would strongly urge you to have an electrician help you implement it. There isn't any way that all of us on this forum are going to be able to ensure that all the considerations needed in your home are accounted for to ensure that you are able to charge safely.

As suggested the EVSEUpgrade is a very cost effective choice combined with your existing dryer circuit but this still needs to be checked out by an electrician and they should help you with any modifications needed to make charging more convenient.
Click to expand...

Ditto QueenBee. I've worked with electricity and electronics for over 30 years. I'm not at all comfortable instructing over the internet how this could be done safely. How far is the dryer from the garage? How do you plan to run the wire to the garage? Do not use extension cords, do not attempt self wiring. Based on your posts, you do not have the skills and experience to do this yourself. As far as using your existing dryer outlet, the switch and a second outlet is a good idea. I don't believe that dryer outlets are designed to have the plug removed and inserted several times a week, year after year. I might be wrong about that, but with electricity inside one's home, I tend to error on the side of safety.
 
kentuckyleaf: Can you (or anybody else) recommend a really good reference for learning safe electrical practices in the home suitable for most homeowners?
 
MikeD said:
kentuckyleaf: Can you (or anybody else) recommend a really good reference for learning safe electrical practices in the home suitable for most homeowners?
Click to expand...

I'm not terribly comfortable answering this. I've never read a book that tells you how to insure you properly installed a wire nut, stripped a cable without scoring it, torque panel screws, and the like. Some of this is a skill that you learn by doing it wrong, and having someone that knows how to do it correctly show you your mistake. I'm not saying that it is difficult at all, it is really simple actually, but when someone's understanding of electricity is such that "you need a transformer to change current in an outlet," they have a long way to go before they try this themselves. I would suggest that anyone that wants a basic understanding of electricity and electronics first read Forrest M Mimms III's book Getting Started in Electronics
ir
and actually do a few of the projects.
 

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