14-30 Question.

[Xire]

Electrical and Tesla newb here. Question...Main panel is only 110 volts and I have a sub panel in my detached garage that I could add a 30 amp breaker to. Right now I'm charging with 120v mobile connect getting 4mph which isn't terrible but not ideal kind term. At first I was going to install the wall charger (got a quote for $650 for the 30a and charger install) but now I think it'll be equal mph to a 14-30 outlet which should be cheaper right? How much mph will I get with both set ups? From what I've researched so far I can only get 24 amps max with either-or correct? Thanks in advance.

 

[Xire]

I'd want to check the conductor size leading out to the garage subpanel. It >might< be big enough for 30 amps. (Trust but verify, even for professionals' work).

I'd want someone to do a load calculation for that main panel. It looks already on the edge of overloaded.

Yeah i don't have enough capacity for 60amp so 30 is the only option for me.

 

[Cosmacelf]

Ok, to summarize. You want to use the garage subpanel since that’s the closest. Looks like a 30A breaker will work there (out of curiosity, what’s the garage 20A breaker used for now?). And yes, installing a 30A 14-30 receptacle is the cheaper way to go since you already have a mobile connector. By code, you’d need to use a 30A GFCI breaker.

Only thing I saw that was weird in your subpanel wiring is that the feeder ground and neutral was bonded in the subpanel. That feeder ground wire should be attached to the ground terminal block, not the neutral terminal block.

Incidentally, you could wire the new circuit/breaker onto the main panel if that’s a shorter/easier route, it’s all the same as far as load goes.

 

[Cosmacelf]

I'd want to check the conductor size leading out to the garage subpanel. It >might< be big enough for 30 amps. (Trust but verify, even for professionals' work).

I'd want someone to do a load calculation for that main panel. It looks already on the edge of overloaded.

It really doesn’t look overloaded to me at all. Easily can support a 24A continuous load.

 

[Sophias_dad]

Only thing I saw that was weird in your subpanel wiring is that the feeder ground and neutral was bonded in the subpanel. That feeder ground wire should be attached to the ground terminal block, not the neutral terminal block.

Good catch... I rest my case regarding "trust, but verify" for professional's work.

 

[Sophias_dad]

It really doesn’t look overloaded to me at all. Easily can support a 24A continuous load.

Maybe... I see 30+40+15 and that's only the dryer/range/AC . Sure, the AC is likely to only take 10, but a full-on range and dryer will potentially take nearly their entire capacity(admittedly not for hours at a time).

Lets assume 30+40+10 worst case, leaving 20 more for all the other loads(admittedly mostly single pole). Add a refrigerator and microwave on the same phase and you might be over 100. Its a stretch, and they are intermittent loads, but not impossible.

I'd still take a look at the nameplate ratings of the dryer/range/AC to see their worst-case-continuous loads.

 

[fholbert]

I'd want to check the conductor size leading out to the garage subpanel. It >might< be big enough for 30 amps. (Trust but verify, even for professionals' work).

I'd want someone to do a load calculation for that main panel. It looks already on the edge of overloaded.

And see if all the breakers are being used. I lived here over 20 years, after buying the Tesla I inventoried the panel and found a retired 240v 50a circuit. Neighbor said the owner before me had a big compressor in the garage.

 

[Cosmacelf]

Maybe... I see 30+40+15 and that's only the dryer/range/AC . Sure, the AC is likely to only take 10, but a full-on range and dryer will potentially take nearly their entire capacity(admittedly not for hours at a time).

Lets assume 30+40+10 worst case, leaving 20 more for all the other loads(admittedly mostly single pole). Add a refrigerator and microwave on the same phase and you might be over 100. Its a stretch, and they are intermittent loads, but not impossible.

I'd still take a look at the nameplate ratings of the dryer/range/AC to see their worst-case-continuous loads.

It’s 25 for the dryer, intermittent. 30 for the range, very intermittent. 12 for the A/C intermittent. Only the A/C runs at night when the charger will be used. I have zero problems with that panel.

 

[Xire]

A good electrician can shuffle things around your main panel to make room for 240V breaker. If the panel supports it, slim tandem breakers can also be used to make room.

On the other hand, if the detached garage is where you park and charge then it seems like the ideal place to setup for charging.

Your choices are

Get a 14-30 outlet installed, assuming your jurisdiction requires GFCI as @jjrandorin, noted that will cost about $50-150 more for just the breaker. You will need $45 for the adapter 14-30 adapter.

Hardwire a wall connector, around $450 for the hardware. The electrician may charge for configuring it (although you should be able also do it yourself). If you do go down this route, make sure it is configured correctly to match the size of the breaker it was installed with.

The actual wire pulls for either option is the same. Both will be on a 30 A circuit

So, mobile connector route saves you around $250-300. If you had to buy the mobile connector, they would be very close to the same.

Man thank you guys so much...i learned a lot from this

Ok, to summarize. You want to use the garage subpanel since that’s the closest. Looks like a 30A breaker will work there (out of curiosity, what’s the garage 20A breaker used for now?). And yes, installing a 30A 14-30 receptacle is the cheaper way to go since you already have a mobile connector. By code, you’d need to use a 30A GFCI breaker.

Only thing I saw that was weird in your subpanel wiring is that the feeder ground and neutral was bonded in the subpanel. That feeder ground wire should be attached to the ground terminal block, not the neutral terminal block.

Incidentally, you could wire the new circuit/breaker onto the main panel if that’s a shorter/easier route, it’s all the same as far as load goes.

And see if all the breakers are being used. I lived here over 20 years, after buying the Tesla I inventoried the panel and found a retired 240v 50a circuit. Neighbor said the owner before me had a big compressor in the garage.

Ok, to summarize. You want to use the garage subpanel since that’s the closest. Looks like a 30A breaker will work there (out of curiosity, what’s the garage 20A breaker used for now?). And yes, installing a 30A 14-30 receptacle is the cheaper way to go since you already have a mobile connector. By code, you’d need to use a 30A GFCI breaker.

Only thing I saw that was weird in your subpanel wiring is that the feeder ground and neutral was bonded in the subpanel. That feeder ground wire should be attached to the ground terminal block, not the neutral terminal block.

Incidentally, you could wire the new circuit/breaker onto the main panel if that’s a shorter/easier route, it’s all the same as far as load goes.

Ok yes EXACTLY that does sum it all up. The 20 a was used by previous home owner who had a compressor in the garage which is why I belive he added the sub panel thank goodness or it would cost a fortune to do that now. so in getting a 14-30 outlet I still need a 3o amp breaker installed correct? The 14-30 with gfci isn't all I would need right?

 

[Cosmacelf]

Man thank you guys so much...i learned a lot from this

Ok yes EXACTLY that does sum it all up. The 20 a was used by previous home owner who had a compressor in the garage which is why I belive he added the sub panel thank goodness or it would cost a fortune to do that now. so in getting a 14-30 outlet I still need a 3o amp breaker installed correct? The 14-30 with gfci isn't all I would need right?

The GFCI and breaker are one and the same. Instead of a normal 30A/240V breaker, you'd get a 30A/240V GFCI breaker. And then some 10/3 romex or (preferred) 10/3 MC cable run to your receptacle box with a 14-30 receptacle.

And have the electrician fix the feeder ground and he'll be impressed you know your stuff

 

[Xire]

The GFCI and breaker are one and the same. Instead of a normal 30A/240V breaker, you'd get a 30A/240V GFCI breaker. And then some 10/3 romex or (preferred) 10/3 MC cable run to your receptacle box with a 14-30 receptacle.

And have the electrician fix the feeder ground and he'll be impressed you know your

Maaaan thank you! Thank all of you guys! So another question...since I have this 20a to this outlet and its not really being used for anything special could I utilize this space/amperage to help in my situation?

 

[Cosmacelf]

The GFCI and breaker are one and the same. Instead of a normal 30A/240V breaker, you'd get a 30A/240V GFCI breaker. And then some 10/3 romex or (preferred) 10/3 MC cable run to your receptacle box with a 14-30 receptacle.

And have the electrician fix the feeder ground and he'll be impressed you know your stuff

BTW, the electrician can also opt to use PVC or metal conduit like was done for the 20A circuit, that works too. MC cable is just faster, maybe slightly cheaper, but whatever your electrician likes.

 

[Cosmacelf]

Maaaan thank you! Thank all of you guys! So another question...since I have this 20a to this outlet and its not really being used for anything special could I utilize this space/amperage to help in my situation?

If you wanted to, you could re-use the conduit/receptacle box for your 14-30 receptacle. Assuming it was located in a good place for the Mobile Connector and your car. You'd just pull out the 20A wires and pull in 30A wires into that same conduit, throw out the 20A receptacle, replace it with a 14-30, and get a GFCI 30A/240V breaker.

 

[Xire]

If you wanted to, you could re-use the conduit/receptacle box for your 14-30 receptacle. Assuming it was located in a good place for the Mobile Connector and your car. You'd just pull out the 20A wires and pull in 30A wires into that same conduit, throw out the 20A receptacle, replace it with a 14-30, and get a GFCI 30A/240V breaker.

Ahhh ok that may work i'll have to see if my MC will reach from that location...the nose of my MY is in front of that outlet maybe a few feet give or take for shelves and other things but ok thank you plenty!

 

[Eric33432]

It is very easy to do a load study using this app, then you will know if your 100 amp service is OK. You can do this yourself.

But I suspect you are OK installing 30 amp circuit for your Tessie.

Electrical Toolbox

 

[Xire]

It is very easy to do a load study using this app, then you will know if your 100 amp service is OK. You can do this yourself.

But I suspect you are OK installing 30 amp circuit for your Tessie.

Electrical Toolbox

Thank you for your insight. Yeah I think so too after all of the input here and what the electrician stated.

 

[Xire]

Ok, to summarize. You want to use the garage subpanel since that’s the closest. Looks like a 30A breaker will work there (out of curiosity, what’s the garage 20A breaker used for now?). And yes, installing a 30A 14-30 receptacle is the cheaper way to go since you already have a mobile connector. By code, you’d need to use a 30A GFCI breaker.

Only thing I saw that was weird in your subpanel wiring is that the feeder ground and neutral was bonded in the subpanel. That feeder ground wire should be attached to the ground terminal block, not the neutral terminal block.

Incidentally, you could wire the new circuit/breaker onto the main panel if that’s a shorter/easier route, it’s all the same as far as load goes.

I'm going to have the electrician look into the feeder ground thank you for that. Also what did you mean by shorter/easier route for wiring the breaker into the main panel? Since the main is in the house and the sub panel is in the detached garage where the car will charged installing there is ideal correct?

 

[Cosmacelf]

I'm going to have the electrician look into the feeder ground thank you for that. Also what did you mean by shorter/easier route for wiring the breaker into the main panel? Since the main is in the house and the sub panel is in the detached garage where the car will charged installing there is ideal correct?

Yes, if the sub panel is in the garage, then use that one. I just didn’t know if the main panel was also convenient to the garage, obviously it isn’t.

Incidentally, I’d be tempted to leave that 20A receptacle there and run a new circuit for your 14-30 receptacle. A 20A circuit in the garage can be useful from time to time.

 

[MY-Y]

Fix the ground and use a 240v 20A breaker looks like the solution. (The subpanel is a 240v panel.)

 

[Xire]

Yes, if the sub panel is in the garage, then use that one. I just didn’t know if the main panel was also convenient to the garage, obviously it isn’t.

Incidentally, I’d be tempted to leave that 20A receptacle there and run a new circuit for your 14-30 receptacle. A 20A circuit in the garage can be useful from time to time.

Ok gotcha so another question. I was going to post another question but maybe you can help. You seem to very knowledgeable in this area. So you know I'm using mobile connector 120v outlet getting 4mph. So for instance if I needed to fill up and 60 miles would do that, that would be 15 hours correct. So if I get the 14-30 set up let's say I get 20mph with that so to get that needed 60 miles that would take only 3 hours... So would that set up make my bill cheaper because I only needed 3 hours instead of 15 or is it based on the power I consumed and it would make my bill more or less the same?

 

[Cosmacelf]

Ok gotcha so another question. I was going to post another question but maybe you can help. You seem to very knowledgeable in this area. So you know I'm using mobile connector 120v outlet getting 4mph. So for instance if I needed to fill up and 60 miles would do that, that would be 15 hours correct. So if I get the 14-30 set up let's say I get 20mph with that so to get that needed 60 miles that would take only 3 hours... So would that set up make my bill cheaper because I only needed 3 hours instead of 15 or is it based on the power I consumed and it would make my bill more or less the same?

Do you have time of use rates? If so, then being able to charge overnight makes a huge difference. Even if you don’t, charging off 240V is much more efficient for a variety of reasons. Check it yourself using this calculator at the bottom of this page that I maintain: Advice for EV Charging in North America