Gen 3 Wall Connector - Is Surge Protection Already Present, or Is It a Requirement At the Main Panel?

[ACRei]

Good day, everyone.

My main panel isn't too strong. It's just at 100A, but I'm looking to upgrade it this summer to 200A.

Today, my house experienced a power outage. Power returned within 10 min, but I didn't get the chance to turn off the 60A breaker connected to the Gen 3 Wall connector.

To my knowledge, the main panel currently does not a whole house surge protection.

May I please find out -

1. Electricity came back before I had the chance to flip the 60A breaker. Is there likely to be damage to the Wall Connector? Or is it robust enough to survive the return of electricity?
2. A professional installed my Wall Connector and the 60A breaker. They didn't mention anything about installing a surge protector at the main panel. Is a whole home solution mandatory for the G3 Wall Connector?

Thank you for any input.

 

[tm1v2]

What do you mean by "necessary" and "requirement?" Are you asking about US electrical code, or wanting more than that?

I know someone whose Tesla Wall Connector (I don't know which generation) was damaged by a power surge (possibly multiple surges) when electricity was being restored after an outage. Several other plugged in items in his home were damaged as well. It's certainly a thing that can happen. However I don't know if his home had any significant electrical defects or code violations, e.g. poor grounding.

I suggest asking Tesla if they have any recommendations or detail they can share beyond what's in the manual. And let us know if you find out anything useful!

 

[ACRei]

What do you mean by "necessary" and "requirement?" Are you asking about US electrical code, or wanting more than that?

I know someone whose Tesla Wall Connector (I don't know which generation) was damaged by a power surge (possibly multiple surges) when electricity was being restored after an outage. Several other plugged in items in his home were damaged as well. It's certainly a thing that can happen. However I don't know if his home had any significant electrical defects or code violations, e.g. poor grounding.

I suggest asking Tesla if they have any recommendations or detail they can share beyond what's in the manual. And let us know if you find out anything useful!

That's definitely frightening.

I'd rather play it safe and have one. However, as I'm not an electrician, there's so much I don't know. E.g., if there is whole house surge protector, can I do away with all my APC surge protectors and just use outlet multipliers? Will the UPS backup for my PC still provide surge protection, or will that feature be nullified by the whole house surge protector?

The Gen 3 Wall Connector manual only had a section regarding GFCI, and continuous ground monitoring in the USA. Unfortunately, it had little to say about requiring a whole house surge protector (my biggest question).

 

[tm1v2]

That's definitely frightening.

I'd rather play it safe and have one. However, as I'm not an electrician, there's so much I don't know. E.g., if there is whole house surge protector, can I do away with all my APC surge protectors and just use outlet multipliers? Will the UPS backup for my PC still provide surge protection, or will that feature be nullified by the whole house surge protector?

The Gen 3 Wall Connector manual only had a section regarding GFCI, and continuous ground monitoring in the USA. Unfortunately, it had little to say about requiring a whole house surge protector (my biggest question).

Careful with phrasing. The Wall Connector most definitely does not require whole home surge protection. Whether it could benefit from that is your question, and seems like a valid one.

In terms of basic cost vs dollar benefit, almost certainly makes zero sense to invest in whole home surge protection capable of handling major surges, just to protect a Wall Connector or two. Wall Connectors are cheap (relatively speaking), and if the surge was from the utility (as opposed to say lightening), you could probably get reimbursed for the damages (at the cost of time and hassle).

For sure it would be more convenient to not have your Wall Connector(s) fried in the first place of course.

Now if you have other reasons for seeking out whole home surge protection, I imagine the Wall Connector could theoretically benefit, but I'm really just guessing.

 

[Sophias_dad]

There's no need to flip the breaker off during restart. The HPWC is likely no more sensitive than any other electronics in your home.

The HPWC won't even try to restart charging to the car until at least three minutes after the power supply is available. There's a random timer so the electric company doesn't have a tremendous demand as dozens, hundreds, or even thousands of Tesla's all start charging at the same moment.

 

[rotarypower101]

Like OP have a "Lower" amperage sub panel, but in the shop.

Is there a prescribed source amperage the panel should have/be fed with when utilizing a 60A breaker for charging and running up to ~48A constant load for the wall connector?

Is there a prescribed overhead the source sub panel should have to feed the wall connector, or as long as the panel has the sufficient amperage to drive the wall charger and other circuits it is viable ?

Like OP, could increase the size of the sub panel breaker from the main panel, but just researching the topic to understand basic details first.

 

[Sophias_dad]

Like OP have a "Lower" amperage sub panel, but in the shop.

Is there a prescribed source amperage the panel should have/be fed with when utilizing a 60A breaker for charging and running up to ~48A constant load for the wall connector?

Is there a prescribed overhead the source sub panel should have to feed the wall connector, or as long as the panel has the sufficient amperage to drive the wall charger and other circuits it is viable ?

Like OP, could increase the size of the sub panel breaker from the main panel, but just researching the topic to understand basic details first.

I'm not sure I understand your questions. I'm also not sure there are two questions there.

There's nothing saying you can't hang a 60 amp subpanel off a 60 amp breaker in the main and then put a 60 amp breaker in the subpanel which connects to a 48 amp HPWC load. Technically there's no extra load available in that subpanel, but if you are just putting a few lights and a garage door opener in there in addition to the HPWC it would still work fine. You'll begin having nuisance trips if you run a large shop-vac or heating unit for sure.

As far as the main panel goes, you'd need to do a load calculation to see if you have the excess capacity available. There's nothing saying your 60 amp main panel can't feed a 60 amp subpanel in your garage.... but it would be stupid.

There's also nothing saying you NEED a 60 amp circuit for an HPWC. I'm not sure where people seem to be getting this. Even a 15 amp breaker(12A charging) can be configured. IMHO, most people could get by with a 20-30 amp charging circuit.

 

[rotarypower101]

I'm not sure I understand your questions. I'm also not sure there are two questions there.

There's nothing saying you can't hang a 60 amp subpanel off a 60 amp breaker in the main and then put a 60 amp breaker in the subpanel which connects to a 48 amp HPWC load. Technically there's no extra load available in that subpanel, but if you are just putting a few lights and a garage door opener in there in addition to the HPWC it would still work fine. You'll begin having nuisance trips if you run a large shop-vac or heating unit for sure.

As far as the main panel goes, you'd need to do a load calculation to see if you have the excess capacity available. There's nothing saying your 60 amp main panel can't feed a 60 amp subpanel in your garage.... but it would be stupid.

There's also nothing saying you NEED a 60 amp circuit for an HPWC. I'm not sure where people seem to be getting this. Even a 15 amp breaker(12A charging) can be configured. IMHO, most people could get by with a 20-30 amp charging circuit.

Just curious, as looking into the topic, and have not seen any detail about the specific scenario that helps me conceptualize, in this case the main panel 200A has plenty of overhead from the main feed, main panel passes 70A via a breaker to a detached shop.

The shops sub panel also has a 70A IN breaker, with several small circuits on it for lighting , 120V outlets and a welder.

So I guess the question is, how do I find out what the prescribed allowable circuits are and their combined load I am allowed to have?

If the sub panel currently has a 70A breaker feed, a single 15A for a lighting circuit, two 15A circuits for 120V outlets , and a 50A 220V for a Welder, can I with NO changes add a additional 60A breaker that can feed 48A continuous to a wall connector? (understanding the wall connector can be modulated for output)

Is the source amperage from the sub panel strictly dependent on how much "Total Load" is drawn from the sub panel at any one time? Regardless of the sum of the other circuits full output?

Or do I need to look at increasing the feed capacity to the sub panel, which I believe I can do because of the wire gauge utilized.

I think the answer is yes, I can add an additional 60A breaker to the sub panel for this purpose with no changes to the feed going to the sub panel, but wanted to explicitly ask describing the scenario to be more certain and confident what I think is not misguided.

 

[Sophias_dad]

Just curious, as looking into the topic, and have not seen any detail about the specific scenario that helps me conceptualize, in this case the main panel 200A has plenty of overhead from the main feed, main panel passes 70A via a breaker to a detached shop.

The shops sub panel also has a 70A IN breaker, with several small circuits on it for lighting , 120V outlets and a welder.

So I guess the question is, how do I find out what the prescribed allowable circuits are and their combined load I am allowed to have?

If the sub panel currently has a 70A breaker feed, a single 15A for a lighting circuit, two 15A circuits for 120V outlets , and a 50A 220V for a Welder, can I with NO changes add a additional 60A breaker that can feed 48A continuous to a wall connector? (understanding the wall connector can be modulated for output)

Is the source amperage from the sub panel strictly dependent on how much "Total Load" is drawn from the sub panel at any one time? Regardless of the sum of the other circuits full output?

Or do I need to look at increasing the feed capacity to the sub panel, which I believe I can do because of the wire gauge utilized.

I think the answer is yes, I can add an additional 60A breaker to the sub panel for this purpose with no changes to the feed going to the sub panel, but wanted to explicitly ask describing the scenario to be more certain and confident what I think is not misguided.

I'm not a professional electrician, but I wouldn't hesitate to add the 60A breaker to the 70A panel. You are definitely not required to add up the maximum raw from all breakers when trying to figure out the remaining available load. That said, if the welder ever gets used while the HPWC is drawing 48 amps, you are virtually guaranteed to trip the breaker going to the subpanel.

With a 48 amp 'real' load on a 70 amp circuit, you have 22 amps still available for temporary use(well, 10 officially, but 22 in reality. Circuit breakers are surprisingly tolerant of overload. I certainly wouldn't be counting on anything like continuous usage of that 22 amps, but if you run a 15 amp shop vac for a few minutes it won't be an issue. Lighting and garage door openers count for almost nothing.

I'm surprised there's a 70A 'in' breaker in the panel as well, but maybe there are no main lugs to connect to directly.

You are technically not supposed to consider loads to be exclusive unless they are automatically exclusive, like heating and air conditioning. That said, I know I wouldn't be welding anywhere near my Tesla, so I'd be fine calling them exclusive loads myself. Additionally, you might consider worst-case if there's a nuisance trip. Your garage is plunged into darkness. If you consider a main panel nuisance trip instead, your entire house might go dark, in the dead of winter, while you are on vacation(ya, its extremely unlikely there'll be an overload with no one in the house, but whatever).

Absolute worst case is you get a 50 amp switch box that either connects your HPWC or your welder to the 50 amp breaker, which guarantees exclusivity.

 

[rotarypower101]

I'm surprised there's a 70A 'in' breaker in the panel as well, but maybe there are no main lugs to connect to directly.

If anyone might be able to comment on that detail, is that a strange method of the incoming power on a detached shops sub panel?

The sub panel does have "Large" main feeder lugs that are Unused and empty in the sub panel. The 70A breaker has the feeder power coming in on the terminals of the breaker feeding into the separate busses.

If I were to guess might that allow resetting a breaker from the shop VS having to go all the way back to the main panel to reset? Or is that not how that would/should work? I don't think the direction of current flow would matter to pop a breaker...But then I dont know the specific details of their internal mechanics.

 

[Sophias_dad]

If I were to guess might that allow resetting a breaker from the shop VS having to go all the way back to the main panel to reset? Or is that not how that would/should work?

If you exceed the 70A limit, its random whether the main panel(feeding) or subpanel(in) 70 amp breaker would trip first.

They might have put in the subpanel backfeed breaker to have a makeshift whole panel shutoff. Maybe that's required where you are.

 

[stopcrazypp]

Just curious, as looking into the topic, and have not seen any detail about the specific scenario that helps me conceptualize, in this case the main panel 200A has plenty of overhead from the main feed, main panel passes 70A via a breaker to a detached shop.

The shops sub panel also has a 70A IN breaker, with several small circuits on it for lighting , 120V outlets and a welder.

So I guess the question is, how do I find out what the prescribed allowable circuits are and their combined load I am allowed to have?

If the sub panel currently has a 70A breaker feed, a single 15A for a lighting circuit, two 15A circuits for 120V outlets , and a 50A 220V for a Welder, can I with NO changes add a additional 60A breaker that can feed 48A continuous to a wall connector? (understanding the wall connector can be modulated for output)

Is the source amperage from the sub panel strictly dependent on how much "Total Load" is drawn from the sub panel at any one time? Regardless of the sum of the other circuits full output?

Or do I need to look at increasing the feed capacity to the sub panel, which I believe I can do because of the wire gauge utilized.

I think the answer is yes, I can add an additional 60A breaker to the sub panel for this purpose with no changes to the feed going to the sub panel, but wanted to explicitly ask describing the scenario to be more certain and confident what I think is not misguided.

Technically, if you have space for it in the panel, especially if not requiring a tandem breaker, you can do it.

Given you appear to be using a backfeed breaker you may have additional limitations (the side with it may be limited in additional breakers you can add):

What is a backfeed main breaker at an electric panel?

www.howtolookatahouse.com

Load calculations are done by going to every appliance/light and looking up how much power they draw (this will typically be much lower than the breaker they are attached to) and adding it up. This should not exceed your sub panel or you run the risk of tripping the breaker to your subpanel. It is not based on adding up the breaker values (otherwise practically every house out there is overloaded).

Account for things like AC which can have a high surge load at startup, but doesn't draw as much during operation.

From your description, it sounds like the main load you can't run simultaneously with your charger is your welder. If you are going to get this inspected, your local jurisdiction may have their own load calculation sheet that may have standard values to use for each type of appliance.

 

[rpiotro]

Technically, if you have space for it in the panel, especially if not requiring a tandem breaker, you can do it.

Given you appear to be using a backfeed breaker you may have additional limitations (the side with it may be limited in additional breakers you can add):

What is a backfeed main breaker at an electric panel?

www.howtolookatahouse.com

Load calculations are done by going to every appliance/light and looking up how much power they draw (this will typically be much lower than the breaker they are attached to) and adding it up. This should not exceed your sub panel or you run the risk of tripping the breaker to your subpanel. It is not based on adding up the breaker values (otherwise practically every house out there is overloaded).

Account for things like AC which can have a high surge load at startup, but doesn't draw as much during operation.

From your description, it sounds like the main load you can't run simultaneously with your charger is your welder. If you are going to get this inspected, your local jurisdiction may have their own load calculation sheet that may have standard values to use for each type of appliance.

I'm not sure that the high surge load at startup would be much of an issue. The US code requires 125% capacity just for that purpose. i.e. a 40 amp rated breaker and wiring for a 32 amp continuous load.

 

[Sophias_dad]

I'm not sure that the high surge load at startup would be much of an issue. The US code requires 125% capacity just for that purpose. i.e. a 40 amp rated breaker and wiring for a 32 amp continuous load.

This is incorrect. AC units are not considered continuous load because they cycle regularly. The 125% is not for surge load. AC makers usually DO specify a considerably larger breaker than the wiring would allow, for motor startup. I'm not sure of the interplay between the NEC rules and such a larger breaker.

The 125% capacity for continuous load is to account for heat buildup in the wire/breaker. In a non-continuous load the wires are given a break where there's little or no heat generated and they can cool during that time.

An EV charger has zero surge loading, they ramp up gently to their max and stop right at the max.

 

[stopcrazypp]

I'm not sure that the high surge load at startup would be much of an issue. The US code requires 125% capacity just for that purpose. i.e. a 40 amp rated breaker and wiring for a 32 amp continuous load.

As another mentioned, AC is not considered a continuous load, so that capacity is not for it. I'm talking instead about for load calculations. For people right at the edge, if you use the operation amps, it's possible for the AC to trip your subpanel or main panel's breaker during startup (even though the AC's breaker won't trip, given as another mentioned, it is typically oversized by a lot for the surge load).

It's enough of a problem that there are plenty of soft start kits available of ACs (people that run generators or backup batteries also would use these).

 

[MikeHolliday]

Good day, everyone.

My main panel isn't too strong. It's just at 100A, but I'm looking to upgrade it this summer to 200A.

Today, my house experienced a power outage. Power returned within 10 min, but I didn't get the chance to turn off the 60A breaker connected to the Gen 3 Wall connector.

To my knowledge, the main panel currently does not a whole house surge protection.

May I please find out -

1. Electricity came back before I had the chance to flip the 60A breaker. Is there likely to be damage to the Wall Connector? Or is it robust enough to survive the return of electricity?
2. A professional installed my Wall Connector and the 60A breaker. They didn't mention anything about installing a surge protector at the main panel. Is a whole home solution mandatory for the G3 Wall Connector?

Thank you for any input.

The "professional" that installed your Wall Connector did not do their job. If you only had an electric dryer and the car charging at the same time, that would be the maximum draw that you can pull from that panel, no air conditioning, no refrigerator, no stove.... You should get your Breaker Panel changed immediately. That is way undersized for a 60 Amp charging circuit. This situation can cause a house fire...

 

[ph0ton]

The "professional" that installed your Wall Connector did not do their job. If you only had an electric dryer and the car charging at the same time, that would be the maximum draw that you can pull from that panel, no air conditioning, no refrigerator, no stove.... You should get your Breaker Panel changed immediately. That is way undersized for a 60 Amp charging circuit. This situation can cause a house fire...

The charger should only be drawing 48 amps (derated), plus either leg of the service can handle 100 amps continuous (depending on your source, some guy apparently contacted the NFPA to confirm in some electrician forums but then another cited some newer feeder regs) so there should be plenty of room for everything.

If OP has nothing but electric everything, then there is nothing to lose in reducing the power output of the wall charger (in the gen 2's there is just a simple dial on the panel).

As to the original question? The wall charger is a dumb relay with a voltage regulator attached to microcontroller. This thing is designed to handle all sorts of ****ery with delivering power and is built to handle more than just service being returned.