Do I need a sub panel. Please help.

[socalev]

Hello,

I have got an on site estimate from a licensed electrician in San Diego who will rearrange some breakers, install 50A breaker and run #4 wire 10 feet on the inside the garage wall behind the panel for $300. He asked me to send him a picture of my panel so he can prepare for this Friday installation. However, I got a phone call from him saying that I might need a 100A sub panel and the new total cost would be $700. I thought that some of my breakers can be rearranged using tandem breakers to make room for the 50A EVSE double pole breaker. Do I really need a sub panel? Thanks for your help.

https://drive.google.com/file/d/0B1J-Iedk5rMgT0RaUk1sX202RkU/edit?usp=sharing" onclick="window.open(this.href);return false;

 

[GlennD]

Since your whole panel is nothing but double breakers you are out of room.

 

[ericsf]

How about moving the double at the bottom left to the right and replace the one above on the left with a quad just like the oven/dryer?

 

[smkettner]

No need for a subpanel. Put the spa on a quad breaker for spa and evse. (similar to the oven/dryer)
Or get a new electrician.

If the spa breaker is a gfi then run the air conditioners together on a quad.

 

[socalev]

How about moving the double at the bottom left to the right and replace the one above on the left with a quad just like the oven/dryer?

That's a great idea. Thanks. Is this what you have in mind?

http://www.lowes.com/pd_151323-296-HOMT2020250CP_0__?productId=3467915" onclick="window.open(this.href);return false;

No need for a subpanel. Put the spa on a quad breaker for spa and evse. (similar to the oven/dryer)
Or get a new electrician.

If the spa breaker is a gfi then run the air conditioners together on a quad.

Thanks for your help. I thought it was ought that he later recommended a sub panel. I searched but could not find a Quad breaker that has 50/50/50/50 combination, only 20/50/50/20 or 30/50/50/30.

 

[TomT]

Keep in mind that there is also a limit as to how much one can load a panel regardless of whether or not the breakers will physically fit... It's called a load calculation and he may be up against this limit which would make it fail an inspection...

 

[Randy]

In the original scenario, I'm curious why you would need a 50 amp breaker and #4 wire...Is this to charge a LEAF?

Why not a 40 amp breaker and #8 wire to deliver 30 amps of charging current?

Like Tom said, the electrician is going to have to submit some load calcs to get the required permit...

 

[ericsf]

Keep in mind that there is also a limit as to how much one can load a panel regardless of whether or not the breakers will physically fit... It's called a load calculation and he may be up against this limit which would make it fail an inspection...

From what I can see on the photo in the first post this panel is already quite overloaded by capacity. He's way over 200A per phase.

 

[socalev]

In the original scenario, I'm curious why you would need a 50 amp breaker and #4 wire...Is this to charge a LEAF?

Why not a 40 amp breaker and #8 wire to deliver 30 amps of charging current?

Like Tom said, the electrician is going to have to submit some load calcs to get the required permit...

I thought since I already spend the money for a 240V outlet, I would like to have some proof for future use with 50A breaker and 40A EVSE. Thanks

Keep in mind that there is also a limit as to how much one can load a panel regardless of whether or not the breakers will physically fit... It's called a load calculation and he may be up against this limit which would make it fail an inspection...

From what I can see on the photo in the first post this panel is already quite overloaded by capacity. He's way over 200A per phase.

I asked my original electrician the same question but he didn't seem to concern about the load. Probably because we have gas for our dryer, the 2 AC units are never on at the same time in the past 10 years and we plan to charge our car from 12-5 AM to receive super off peak rate. So if even we have 1 AC units + EVSE and Spa on at the same time with some lights during the day, I think we won't trip the main service panel. Please let me know if my rational is correct? Thanks

 

[DarkStar]

180 amps in 240 volt loads alone... Only 200 amp service... That's pretty well loaded.

 

[Randy]

There are very few EVSEs on the market that can deliver 40 amps to the car (Leviton, Clipper Creek, and Tesla), and only a couple of cars that will accept a charge above 30 amps (Toyota RAV4EV @ 40 amps, Tesla @ up to 80 amps)...

30 amps is adequate for now. But if you're really serious about future proofing, I think you should be planning for more than 40 amps of charging capability...The extra 10 amps doesn't buy you much...

You may want to charge 2 cars at 30 amps down the road, or you may want to charge a Tesla or some future car at 80 amps, etc.

A sub panel would come in handy if you're planning for that kind of future...

 

[smkettner]

I searched but could not find a Quad breaker that has 50/50/50/50 combination, only 20/50/50/20 or 30/50/50/30.

I think this is a 50/50

http://www.relectric.com/Store/Circuit-Breakers/BQ250250

Or this 40/40 to combine the air conditioners

http://www.relectric.com/Store/Circuit-Breakers/BQ240240

Electrician should have access to all the good stuff.

#6 wire is fine on 50a breaker unless the run is excessive such as over 150'.
Actually #8 is ok for a very short run. Electrician should know this off the top of his head.
#4 is probably overkill.

The J1772 standard plug basically makes you future proof in itself. It will charge all plug in vehicles for many years to come. OK maybe a bit slower than the max but will still charge fine. Probably 40a circuit is fine to charge at up to 32 amps. Otherwise the future will take care of itself.

 

[TomT]

This will give you a rough load calc:

http://www.nojolt.com/load_calculations.shtml" onclick="window.open(this.href);return false;

 

[johnrhansen]

Keep in mind that there is also a limit as to how much one can load a panel regardless of whether or not the breakers will physically fit... It's called a load calculation and he may be up against this limit which would make it fail an inspection...

From what I can see on the photo in the first post this panel is already quite overloaded by capacity. He's way over 200A per phase.

you don't calculate loads by adding up all the circuit breakers. often times they add up to far more than the rating of the panel. It's all been figured out and tested for safety and is published in the National electric code.

 

[mctom987]

Keep in mind that there is also a limit as to how much one can load a panel regardless of whether or not the breakers will physically fit... It's called a load calculation and he may be up against this limit which would make it fail an inspection...

From what I can see on the photo in the first post this panel is already quite overloaded by capacity. He's way over 200A per phase.

you don't calculate loads by adding up all the circuit breakers. often times they add up to far more than the rating of the panel. It's all been figured out and tested for safety and is published in the National electric code.

There is a still a limit to what you can do. I can't imagine trying to hookup a 200A subpanel on a 100A SER.

Generally, the large loads are added up, and the small loads ignored or heavily discounted. This is because almost never would you have all 15A breakers loaded, but doing laundry (30A) and cooking dinner (40A) while the A/C (50A) is on is not exactly a rare scenario. You specifically might not be doing that, but there are more than a few houses without gas service.

 

[smkettner]

Generally, the large loads are added up, and the small loads ignored or heavily discounted. This is because almost never would you have all 15A breakers loaded, but doing laundry (30A) and cooking dinner (40A) while the A/C (50A) is on is not exactly a rare scenario. You specifically might not be doing that, but there are more than a few houses without gas service.

Still the device rating should be used not the breaker.

Example: my two air conditioners are on 40 amp breakers but they draw about 30 amps together. So I think the calculation is based on 30 amps not 80 amps.

 

[socalev]

There are very few EVSEs on the market that can deliver 40 amps to the car (Leviton, Clipper Creek, and Tesla), and only a couple of cars that will accept a charge above 30 amps (Toyota RAV4EV @ 40 amps, Tesla @ up to 80 amps)...

30 amps is adequate for now. But if you're really serious about future proofing, I think you should be planning for more than 40 amps of charging capability...The extra 10 amps doesn't buy you much...

You may want to charge 2 cars at 30 amps down the road, or you may want to charge a Tesla or some future car at 80 amps, etc.

A sub panel would come in handy if you're planning for that kind of future...

This is a very sound advice. Thank you. I was thinking along the line of pulling out the dryer outlet line and connect its 30 A breaker to an outlet for EVSE as it's the cheapest way of getting this task done.

If I decide on sub panel, I'd like to be able to accommodate bigger breaker and solar panel ( as it's also under my consideration).

I searched but could not find a Quad breaker that has 50/50/50/50 combination, only 20/50/50/20 or 30/50/50/30.

I think this is a 50/50

http://www.relectric.com/Store/Circuit-Breakers/BQ250250

Or this 40/40 to combine the air conditioners

http://www.relectric.com/Store/Circuit-Breakers/BQ240240

Electrician should have access to all the good stuff.

#6 wire is fine on 50a breaker unless the run is excessive such as over 150'.
Actually #8 is ok for a very short run. Electrician should know this off the top of his head.
#4 is probably overkill.

The J1772 standard plug basically makes you future proof in itself. It will charge all plug in vehicles for many years to come. OK maybe a bit slower than the max but will still charge fine. Probably 40a circuit is fine to charge at up to 32 amps. Otherwise the future will take care of itself.

Thanks for your help. I kind of have some doubt as why my electrician could not figure it out in the first place. He said I need a sub panel since I don't have any slot left, not because he was concerned about the load which I asked him when we met last week.

Keep in mind that there is also a limit as to how much one can load a panel regardless of whether or not the breakers will physically fit... It's called a load calculation and he may be up against this limit which would make it fail an inspection...

From what I can see on the photo in the first post this panel is already quite overloaded by capacity. He's way over 200A per phase.

you don't calculate loads by adding up all the circuit breakers. often times they add up to far more than the rating of the panel. It's all been figured out and tested for safety and is published in the National electric code.

That's what I understood from reading from various sites since yesterday. That's why I mentioned Gas dryer in my previous post and we also use gas for cooking as well. I was thinking 200A service panel can handle a lot unless someone decides to turn every single appliance in the house on at the same time.

 

[mctom987]

Generally, the large loads are added up, and the small loads ignored or heavily discounted. This is because almost never would you have all 15A breakers loaded, but doing laundry (30A) and cooking dinner (40A) while the A/C (50A) is on is not exactly a rare scenario. You specifically might not be doing that, but there are more than a few houses without gas service.

Still the device rating should be used not the breaker.

Example: my two air conditioners are on 40 amp breakers but they draw about 30 amps together. So I think the calculation is based on 30 amps not 80 amps.

Are you talking about 120V or 240V units? Are you saying they are 15A each?
240V circuits generally use two fuses. 120V 40A + 120V 40A = 240V 40A. This is because a 240V outlet can use 120 or 240V, and often do on things like clothes dryers. Both live lines need to be fused, as it's possible to pull more than 40 on either of them, without tripping the other.

32A is the max continuous load on a 40A breaker. If your device is 30A, 40A is only overshooting it by 6%.

 

[pchilds]

This will give you a rough load calc:

http://www.nojolt.com/load_calculations.shtml" onclick="window.open(this.href);return false;

I better not try to permit anything, it says I need 300+ amps and I only have 200 amp service. :shock:

 

[smkettner]

240v, I think they are 2.5 ton each.
I think a clothes dryer is about 4500 watts or less than 20a draw on that 30a breaker.