Preparing wiring for ekettle and Nissan Leaf

[CCinBR200]

I'm hoping to check my plans out with the smart folks here.

My wife and I are planning to convert our kettle to electric. I am also planning to buy a Nissan Leaf so want to prepare for its charging.

I already have a run out out to the exterior of our "music/hobby room". But, it is 20amp and so has 12awg wire. The Nissan pulls close to 30amps so it will need 40amp service.

Since our electric stove was replaced with a gas one, I can remove a 2-pole 30amp breaker and replace with a 40amp non-GFCI breaker. From this breaker, I will use 8awg 4-conductor wire to the end of my current run, removing all 12awg wire.

This will terminate to a spa panel with 40amp GFCI:
http://www.homedepot.com/p/Eaton-40...Panel-with-Self-Test-GFCI-CH40SPAST/206696141

I will place double-pole 40amp and 30amp non-GFCI breakers in the spa panel. The 40amp breaker will later feed the Leaf charger. The 30amp will feed out to a 4-conductor dryer-style receptacle for the controller and kettle. From there, I will follow P-J's approach to building a controller.

Considering how often we brew, I don't think there is much chance we'd forget and try to brew while charging the car. I know there are ways to lock the other out when one of those processes starts, but not sure if it's necessary. Open to ideas about how to do that though.

Any obvious problems with my plan? Thanks for any help. I have learned a lot reading the sticky for this topic and lots of other posts.

 

[timdillon36]

If you put an interlock in the spa panel so that only one breaker can be on at a time that should keep you safe and to code. The interlock is a simple mechanical 'stop' that will only allow this or that breaker to be on but not both.

Or you could do one gfi in the main panel to one outlet and plug in the car or the brew rig.

Off topic, the carbon footprint to build a hybrid or electric car is bigger than building and running a ICE car for years.

 

[doug293cz]

Doesn't code require the Leaf charging outlet to have GFCI protection since it will be exposed to the weather or in the garage?

Brew on

 

[CCinBR200]

Doesn't code require the Leaf charging outlet to have GFCI protection since it will be exposed to the weather or in the garage?

Brew on

I think that the 40amp breaker for the Leaf being placed in the Spa Panel would also be GFCI-protected by the Spa Panel's GFCI. Correct?

Thanks!

 

[doug293cz]

I think that the 40amp breaker for the Leaf being placed in the Spa Panel would also be GFCI-protected by the Spa Panel's GFCI. Correct?

Thanks!

Yep, I misread OP's plan as putting the non-GFCI breakers in the main panel ahead of the spa panel which would only provide GFCI protection to the 30 outlet for the brewery. After rereading, I see the plan is to put the non-GFCI breakers in the spa panel downstream of the GFCI.

Brew on

 

[jeffmeh]

I would check to make sure that the additional breakers in that spa panel are truly downstream of the GFCI breaker. I believe that some of them are configured such that the lines in run in parallel to each breaker, at least by default.

 

[CCinBR200]

I would check to make sure that the additional breakers in that spa panel are truly downstream of the GFCI breaker. I believe that some of them are configured such that the lines in run in parallel to each breaker, at least by default.

Thanks! I'll check into that. That would certainly change the game.....

 

[CCinBR200]

I would check to make sure that the additional breakers in that spa panel are truly downstream of the GFCI breaker. I believe that some of them are configured such that the lines in run in parallel to each breaker, at least by default.

Looking harder at the spa panel, it does seem that added breakers will not share GFCI protection. So........... the following is my revised plan.

Place 40A GFCI breaker in main service panel. Then, 8awg 4-conductor run to a sub-panel. Place 40A and 30A breakers in that panel as above.

I welcome any questions or concerns about this plan. Alternately, it would boost my confidence to be told that it makes good sense.

Thanks!

 

[itsnotrequired]

Looking harder at the spa panel, it does seem that added breakers will not share GFCI protection. So........... the following is my revised plan.

Place 40A GFCI breaker in main service panel. Then, 8awg 4-conductor run to a sub-panel. Place 40A and 30A breakers in that panel as above.

I welcome any questions or concerns about this plan. Alternately, it would boost my confidence to be told that it makes good sense.

Thanks!

my thoughts would be to skip the sub panel altogether. put a gfci breaker in your main panel and run it to an appropriate single receptacle in the garage. plug in either the car or the brew panel. get a plug on your brew panel to match the receptacle for the charging station.

 

[CCinBR200]

my thoughts would be to skip the sub panel altogether. put a gfci breaker in your main panel and run it to an appropriate single receptacle in the garage. plug in either the car or the brew panel. get a plug on your brew panel to match the receptacle for the charging station.

Thanks for this thought. Question, though: Leaf draws 30A so I think it needs a 40A breaker. Brew kettle draws in the 20's amps so I think it needs a 30A breaker. If I ran the kettle from a 40A breaker, doesn't that provide inadequate protection?

I appreciate all ideas and questions.

 

[stevehaun]

Put 30 amp fuses or a 30 amp breaker in your control panel.

 

[doug293cz]

Thanks for this thought. Question, though: Leaf draws 30A so I think it needs a 40A breaker. Brew kettle draws in the 20's amps so I think it needs a 30A breaker. If I ran the kettle from a 40A breaker, doesn't that provide inadequate protection?

I appreciate all ideas and questions.

You can run the brewery from the 40A breaker, as long as the high current wiring is 8AWG. If you want to drop down to 10AWG wire for the brewery, you need 30A fuses, or a 2 pole 30A breaker, at the transition from 8AWG to 10AWG. You would need to fuse both hot lines.

Brew on

 

[itsnotrequired]

Thanks for this thought. Question, though: Leaf draws 30A so I think it needs a 40A breaker. Brew kettle draws in the 20's amps so I think it needs a 30A breaker. If I ran the kettle from a 40A breaker, doesn't that provide inadequate protection?

I appreciate all ideas and questions.

check the specs on your charging unit for the leaf, it will tell you what you need. quick look on the internet indicates many chargers, some at 120 volt.

and to mimic others, put a main breaker in your brew panel if it is smaller than the charging unit.

 

[CCinBR200]

Ok, I get it. So it's safe to have 40A protection for the brew kettle so long as I use proper sized wire (8awg).

So, tell me if I have my 2 basic choices right:

1) 40A GFCI breaker in service panel --> 8awg run ---> 50A 240v receptacle -----> Leaf charger or kettle controller power cord ---> all high power wires inside controller are 8awg

2) 40A GFCI breaker in service panel --> 8awg run ---> 50A 240v receptacle -----> Leaf charger or kettle controller power cord ---> 30A breaker within controller ------> 10awg inside controller

Would you consider #1 inherently safer? I will have enough 8awg to wire the controller with it.

P.S. Here's a recommended receptacle for the Leaf charger:
http://www.amazon.com/dp/B00004YUNT/?tag=skimlinks_replacement-20

And, BTW, I actually could use my existing 120v GFCI receptacle to charge a Leaf at half the speed of a 240V setup (and that would probably be fine for almost all my charging needs). But, at half the speed AND I wouldn't get to play with all these interesting things.

You folks are great! Thank you for the help! :rockin:

 

[lschiavo]

Option 2. Your panel components cannot be rated less than your breaker. 30A components are much cheaper.

 

[doug293cz]

Option 2. Your panel components cannot be rated less than your breaker. 30A components are much cheaper.

Care to explain? There are lots of examples of electrical devices around the home that have internal components rated for lower currents than the supply circuits into which they are plugged. My understanding is that breakers/fuses are meant to protect the wires from overheating and creating a fire hazard, so as long as the wire is rated to handle at least the current limit of the breaker/fuse, then you are legit.

Brew on

 

[lschiavo]

Care to explain? There are lots of examples of electrical devices around the home that have internal components rated for lower currents than the supply circuits into which they are plugged. My understanding is that breakers/fuses are meant to protect the wires from overheating and creating a fire hazard, so as long as the wire is rated to handle at least the current limit of the breaker/fuse, then you are legit.

Brew on

Sorry. I was on my last beer for the night when I posted that

First thing in a control panel is usually a switch or contactor. You cannot use a switch rated 30A if the breaker upstream is rated higher. Same goes for a receptacle and plug for an element. The device rating is the max current they can handle. You could potentially overload them if connected to too large a circuit.

The fuse/breaker does protect the wiring downstream. The devices used are part of that wiring.

If the "devices" you mention are manufactured and UL listed, they are wired using a different set of rules than field wiring. We are doing field wiring when we build control panels.

 

[CCinBR200]

Hello again.

My wife and I made the decision to go with a subpanel so that we could also add a 120v receptacle.

We've been busy ordering parts.

I came upon an electrician video saying that a subpanel a distance away from the main service panel would require it's own grounding rod.

We have 8AWG 4-conductor wire (includes ground wire) to make the run from the main service panel to the subpanel. The subpanel is outside and about 40 ft away. Do we need a separate ground rod for the subpanel? Is that what the spa panels require when they are used to power a hot tub?

Thanks!

 

[lschiavo]

The way I have always read the code is you need a grounding electrode at every separate structure. If you are on the same structure as your main service panel, you do not need another rod.

 

[itsnotrequired]

The way I have always read the code is you need a grounding electrode at every separate structure. If you are on the same structure as your main service panel, you do not need another rod.

this is correct. if a subpanel is located in a detached structure, a grounding electrode system needs to be established at the structure. if you only bring a single branch circuit to a structure (e.g. for a light), additional grouniding electrodes are not required at the structure.

a single ground rod does not totally meet code unless it can be demonstrated that the resistance between the rod and earth is less than 25 ohms. this was a new requirement starting in the 2011 code revision. if the resistance cannot be met, an additional grounding electrode is required (no additional testing). for detached structures, this is typically accomplished via a second ground rod. the rods need to be at least 6' apart from each other.

rarely is the single rod tested for acceptable resistance to earth as the test itslef costs many times more than a second rod. here in wisconsin, the state electrical code won't even let you test the rod. they require a second grounding electrode in all instances.

from a practical standpoint, little is gained by adding grounding electrodes at a detached structure such as a shed or similar. if you want to meet code, put the rods in but if you don't, there is not any measurable safety concern. for example, i believe it is not required in canada unless the detached structure has livestock.