How many amps for new 240V install?

Oilpan4 said:

Aluminum wire inside an inhabited structure?
Hell no.

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The wires from the street into the breaker box are often aluminum. That is in an inhabited structure. There are 100 million houses done that way, and these wires don't cause problems. Aluminum can be safe if done correctly.

There were millions of houses built with interior aluminum wiring not done correctly. A few burnt down. That's a good reason to be very shy of aluminum wiring, especially in houses built in the 1960's and 1970's. But a new house? I'd be skeptical, but would consider it. Show me the test data. Show me houses built with this technology that have been around for a decade or more.

Yeah I crimp live service drops. They're aluminum from the transformer to the house. Normally from the weather head into the house is copper.
From the weather head to the panel is one of the few places aluminum can be properly installed in a home since one end is crimped and the other end is in big screw terminals.
The inspectors in Texas and new Mexico don't like aluminum.
They get out their book and start doing calculations and looking at everything closer.

The ultimate guide is "reducing fire hazards in aluminum wired homes"
Last update was 2014 and I believe it's still ongoing.

I read another report that said a homes electrical wiring was something like 50 times more likely to reach a fire hazard condition if it had aluminum branch circuits.

All I know is I have seen a large portion, up to half of aluminum wired homes have some burned wires.

The worst is aluminum wire with a zinsco panel. Those zinsco breakers act more like on off switchs then breakers.

Just to be clear, if I do use Al cable for my garage sub-panel, it will be used from the breaker in the main panel to the sub-panel lugs. Both sides are clearly rated for use with Al. I'm pretty careful about this kind of stuff. Eg. all the receptacles in my house have been replaced with 'spec grade' ones and ALL the 120V breakers in the panel are AFCI or GFCI/AFCI.

Oilpan4 said:

I read another report that said a homes electrical wiring was something like 50 times more likely to reach a fire hazard condition if it had aluminum branch circuits.

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Do not conflate the performance of circa 1970 AA-1350 aluminum wiring with the performance of modern AA-8000 series aluminum wiring.

Cheers, Wayne

I don't believe 8000 series alloy can be purchased for branch circuits.
Even if it could I wouldn't use it.
I don't think aluminum wire smaller than 6 gauge can be purchased for use in residential wiring.
So even if you bought and used aluminum wire in a modern house it would be on a dedicated circuit that starts in the panel and ends at a single receptacle with big screw terminals. No splices, no multi wire junctions, no wire nuts, ect.

Oilpan4 said:

I don't believe 8000 series alloy can be purchased for branch circuits.
Even if it could I wouldn't use it.
I don't think aluminum wire smaller than 6 gauge can be purchased for use in residential wiring.
So even if you bought and used aluminum wire in a modern house it would be on a dedicated circuit that starts in the panel and ends at a single receptacle with big screw terminals. No splices, no multi wire junctions, no wire nuts, ect.

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Close, the smallest you can typically get is #8 aluminum. You can use that for branch circuits, but as you say they would likely be individual branch circuits. Which is what the OP was about, an individual branch circuit for an EVSE. For which aluminum is a fine choice, unless you are hardwiring the EVSE and its spec sheet says "copper conductors only."

Cheers, Wayne

smkettner said:

Unless you are a super commuter 30 amp circuit and 24 amp EVSE is plenty 99% of the time.
Get 40 or 50 if you like but I would rather have 2x 30 amp for two vehicles.
If going 60+ then put it to a subpanel to split the power between multiple EVSE etc.

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IMHO, I would rather one 40 or 50A circuit with two 32 or 40A Power Sharing Electric Vehicle Charging Stations. That gives you the flexibility to quickly charge one car or divide the power between both cars. It would also likely be cheaper than having separate circuits.

The sub-panel route is another good option (especially if you think you may want to have 3 or more charging stations), though in some cases it might be easier to have a main panel in the garage, and make the existing panel for the rest of the house a sub-panel.

I would rather run dedicated lines to each EVSE rather than splicing the wires to multiple EVSE's. There are probably ways to do the splice that is up to code but IMHO, it would be much simpler to run a separate circuit to each EVSE. And in that case, having a sub-panel nearby makes the job much easier.

I'm planning to put a sub-panel in my garage due to some factors that are unique to my situation. I don't plan to install more than one EVSE but if I ever did, the sub-panel should handle it easily. In the mean time, I have some other circuits that need to be updated and that will be much easier with a sub-panel in the garage.

goldbrick said:

I would rather run dedicated lines to each EVSE rather than splicing the wires to multiple EVSE's. There are probably ways to do the splice that is up to code but IMHO, it would be much simpler to run a separate circuit to each EVSE. And in that case, having a sub-panel nearby makes the job much easier.

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To each his own. I would prefer the flexibility offered by Power Sharing for the one time cost of making sure the wiring and configuration are done right (yes, the code does permit this configuration), as I can envisage situations where being able to charge one vehicle faster than the other would be useful.

How do the Power Sharing EVSE's communicate with each other? Is this a dual plug EVSE that has only 1 connection to the power source and then divides the power between them? Is one of these units cheaper than 2 separate EVSE's? or just more convenient?

goldbrick said:

How do the Power Sharing EVSE's communicate with each other? Is this a dual plug EVSE that has only 1 connection to the power source and then divides the power between them? Is one of these units cheaper than 2 separate EVSE's? or just more convenient?

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There is no industry standard. Here are the ones I know of. There may be others.

• The Flo X5 uses HomePlug powerline communication.
• It looks like the ClipperCreak Share2 charging stations use 3 low voltage wires .
• The Tesla Wall Connector has a pair of low voltage wires that connect them in a daisy chain. One is set as a master, with the total currant available and the others are set as slave.

AFAIK, they are hard wired and don't come with a plug, so you would need to connect them together. The ClipperCreek are sold as a pair or as one dual station, but the others are sold individually. The cost savings comes from only needing one breaker and power cable from the panel.

Sounds like a gimic. How much does it cost?
Bet it would be cheaper to run 2 evse circuits with 2 regular no thrills evse units.

Oilpan4 said:

Sounds like a gimic. How much does it cost?
Bet it would be cheaper to run 2 evse circuits with 2 regular no thrills evse units.

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For Flow and Tesla, you just buy a second EVSE at the same price as it is a standard feature on the Flow X5 and all Tesla Wall adapters.

ClipperCreek seems to sell them in bundles that appear to cost more than two individual ones, which seems strange. I don't really know much about their product line though.

EDIT: It looks like all Juice Boxes come with Load Sharing and they use WiFi to communicate with each other, so similar to Tesla and Flo, all you need to do is buy a second EVSE..

The new 120/240v nissan leaf evse that will charge at full 6.6kw are going for about $250 on ebay. It's new, it says nissan on it, comes with 2018 and up leaf. Can't get much better than that.

I'm going to say the fancy line sharing protocol is a gimic if you're installing less than 3 or 4 level 2 chargers.

Oilpan4 said:

The new 120/240v nissan leaf evse that will charge at full 6.6kw are going for about $250 on ebay. It's new, it says nissan on it, comes with 2018 and up leaf. Can't get much better than that.

I'm going to say the fancy line sharing protocol is a gimic if you're installing less than 3 or 4 level 2 chargers.

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If you are confident that it is genuine, then great! It could be a cheap knock off though. You have to careful with cheap EVSEs sold on eBay and Amazon, as many aren't safety certified. Hardly a bargain if it burns your house down. :shock:

Durability is another factor. Cheaply made EVSEs often won't last as long as a good quality one. Those savings go out the window if you have to replace it regularly.

Cheap EVSEs usually don't have smart features. Not only can you set up timers and control the charging rate, but you may be able to subscribe to a demand management program with your utility and save money by letting them control how quickly your car charges to match the demand on the grid. Who cares how quickly your car charges overnight as long as it is fully charged when you leave in the morning. Those savings can add up over the life of your EVSE.

The other factor in all of this is the size of your electrical service. If you have a 200A service, then is is very likely that you can add two additional 40A circuits (what would be needed for the Nissan portable EVSA). If you only have a 100A service, you can probably only get 1 additional 40A circuit. Upgrading your service can cost thousands of dollars.

A 35A circuit is sufficient for a Nissan portable EVSE. 2 of those would draw 55A if both are running at full output. I think many or most 200A services could handle that extra load, although I would strongly recommend that anyone contemplating this have a professional electrician do a load analysis to be sure.

Unless the shared EVSE's have some sort of feed-through power connections this will require making Y-connections in the wiring to the multiple EVSE's. That isn't a trivial matter when working with large gauge wires. It also means the communications between the EVSE's is somewhat safety critical so they don't over-load the circuit if they both turn on full by mistake. Of course the breaker should handle that situation but using wifi or something to limit the current on a circuit is a bit dicey IMHO.

I have a cheap $160, 16 amp 240v duosida evse that I have had for a year and a half.

If the panel is full add a sub.

No need to do a load analysis on residential. That's what the main breaker is for. If anything switch breakers around to ballance both legs of 120v current flow.
Panels are designed to be safe as long as codes are followed. That's why they are a certain physical size, have a max main breaker rating and only allow a certain numbers of circuits to be installed.

goldbrick said:

A 35A circuit is sufficient for a Nissan portable EVSE. 2 of those would draw 55A if both are running at full output.

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Does the Nissan EVSA limit the current to 28A (current limiting is in 1A steps in the J1772 protocol) or is its limit higher and the charger inside the Leaf is the one limiting the current to 27.5A. Plugging a load that is capable of drawing more than 80% of the circuit's maximum would be a code violation. Ignoring that, wiring 35A breakers to a NEMA 14-50 outlet is asking for a wold of pain in the future. At some point someone will plug a 32A (or maybe even a 40A) EVSA into the outlet (with a car capable of drawing that much current) and that would result in the breaker tripping.

I think many or most 200A services could handle that extra load, although I would strongly recommend that anyone contemplating this have a professional electrician do a load analysis to be sure.

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For those lucky enough to have a 200A service, sure (I even said that in my previous post), but if you only have a 100A service, it would be a stretch.

Unless the shared EVSE's have some sort of feed-through power connections this will require making Y-connections in the wiring to the multiple EVSE's. That isn't a trivial matter when working with large gauge wires. It also means the communications between the EVSE's is somewhat safety critical so they don't over-load the circuit if they both turn on full by mistake. Of course the breaker should handle that situation but using wifi or something to limit the current on a circuit is a bit dicey IMHO.

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I believe that when configured in shared mode, if it loses communication with the other station, it would fall back to 50% to keep things safe, but that would need to be verified. They are UL certified, so there must be some sort of safety mechanism beyond letting the breaker trip.

Oilpan4 said:

I have a cheap $160, 16 amp 240v duosida evse that I have had for a year and a half.

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From what I have heard, that is about the average life expectancy for cheap EVSAs. Maybe you will be lucky and get 3-4 years out of it. A good one should last over 10 years.

If the panel is full add a sub.

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I said if the service is full, not if the panel is full. Adding a sub panel allows you to add more breakers, but it won't increase the capacity of the service (in Amps). Increasing the service size likely means dragging in a new wire from the transformer (unless the one you have happens to be oversized) which is going to be very expensive (especially if you have underground wiring).

No need to do a load analysis on residential. That's what the main breaker is for. If anything switch breakers around to ballance both legs of 120v current flow.

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The main breaker is designed to protect you from exceptional circumstances, not to protect you from blindly adding additional circuits until you are over capacity. Having any circuit breaker blow is a warning that something isn't right, but having the main breaker blow is a sign that something is very seriously wrong. It should not be relied upon as a test that everything is okay.

Panels are designed to be safe as long as codes are followed. That's why they are a certain physical size, have a max main breaker rating and only allow a certain numbers of circuits to be installed.

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That is the key. Part of the code requirement is that you not put more load on the panel than the service was intended for.

goldbrick said:

I would rather run dedicated lines to each EVSE rather than splicing the wires to multiple EVSE's. There are probably ways to do the splice that is up to code but IMHO, it would be much simpler to run a separate circuit to each EVSE. And in that case, having a sub-panel nearby makes the job much easier.

I'm planning to put a sub-panel in my garage due to some factors that are unique to my situation. I don't plan to install more than one EVSE but if I ever did, the sub-panel should handle it easily. In the mean time, I have some other circuits that need to be updated and that will be much easier with a sub-panel in the garage.

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It's actually easiest to use a subpanel to "split" the power when doing the power sharing thing. You run your 50a feeder (or whatever size) circuit into the subpanel, then two more 50a circuits from the subpanel to each EVSE. The EVSEs manage the load so you don't overdraw the feeder circuit.