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Rare = local practice, I don't know if it's just convention or if the POCO won't like it for some reason. Only if you are able to use the Backup Meter Switch, again which I don't know the CA approval status of. If you are using the Backup Gateway 2, then you'd need to have all your backed up...

2x - 4x cost difference between CA and NH. Cheers, Wayne

Mostly yes. The internal panelboard may be able to handle the role of the PW panel, using quad 30/30 breakers (each of which supports 2 double pole 30A circuits and takes up 2 of the 6 spaces). I'm not up on the details of whether there's a snag in that idea--a while back there was a...

Economically, the value benefit of (avoiding 1 kWh of peak grid usage by grid charging 1.1 kWh off peak) is the same as that of (gaining 1 kWh of peak export by foregoing 1.1 kWh of off peak export), since the NBCs are same off peak and peak. (Right? Just double checking). But as grid export is...

I took a closer look at the manual, and I see it says "Ground Fault Circuit Interrupter Integrated -- no additional required (CCID20)." That term CCID20 is apparently from UL 2231-2 and refers to a 15-20 ma trip threshold. So the Wall Connector does not provide Class A GFCI protection. And...

Does anyone know the ground fault current at which the Tesla Gen 3 Wall Connector will trip? The manual says it has a GFCI built-in, but it doesn't specify a Class or trip threshold. Your typical GFCI receptacle is Class A which means it has to trip at 4-6 ma. Then there's Class B and Class C...

Based on Redhill_qk's description of what CRD-PCS means (I didn't read the link), how can the GW2 be so certified when you can enable both "grid charging" and "export everything"? Or does Tesla have the ability on the backend to make those mutually exclusive, and you can request they do so, and...

Not typical, but common. See Tesla surprises with a $4800 bill on existing $5300 install contract for info on this specific case. Yes, there are. But then you have to upgrade your service panel with the resulting costs and potential PG&E hassle (particularly if you have a gas riser within 36"...

Yes, 22.3A is allowed for the Optional Method. I took another look at the SJ form again, and the "NEW" section doesn't specify a load factor. It also doesn't have much room--I'd be inclined to include an addendum with that form that includes the new loads along with their load factors, adds...

I haven't tracked down the primary sources again to give you references, but if you do, my recollection is that this is what you will find: Prior to the IRA, (the relevant part of) the ITC law wording was basically about PV systems. So the question was what is the status of an ESS that is...

Code reference? Cheers, Wayne

Correction: MCA is basically the sum of the loads in the unit plus an extra 25% of the largest motor; for an A/C outdoor unit that largest motor is usually the compressor and the nameplate value for it is RLA (rated load amps). For the optional load calc, you only need the sum of the loads...

Does that mean there are reset procedures that are only possible to do on systems with 2 or more PWs? With no alternative procedure for systems with just 1 PW? Cheers, Wayne

How did the system end up in that circumstance? I thought this thread was for the case of off grid and PWs offline because they hit the low charge level self-protection limit. And then you have to do a "cold start" to bring them back online, presumably with all loads turned off and the sun...

OK, do you know if there is a technical reason for that? Possibly related to the "open loop response time" that the PCS has, which will briefly allow export in excess of the limit? Cheers, Wayne

Can't you just set the site export limit based on the loop impedance test? Then it would just be an issue for exporting and doing TOU arbitrage. Cheers, Wayne

Apparently it does include a Gateway. If you answer "yes" to "Are you expanding a Powerwall System?" then the prices go down by $1,000. Looks like the price is $200 (shipping/overhead) plus $1,000 for the Gateway (if required) plus $8,000 per PW. Cheers, Wayne

I should say "with a DMM". What can be done is a different sort of impedance test, and I think there are more expensive purpose built meters that do it. Namely, for two conductors that have power between them (H-N, or H-G if there's no ground fault protection upstream), impose a varying...

You're apparently missing the point of the test I did, so let me explain: We have a dummy resistance with two terminals R1 and R2. We have a branch circuit receptacle with terminals N and G. I connected R1 to G, and then measured resistance R2 to N. The dummy resistance represents a fault in...

Did you completely miss post #121? https://teslamotorsclub.com/tmc/threads/mobile-connector-flashes-2x-%E2%80%9Cground-loss%E2%80%9D.295261/page-7#post-7480056 Cheers, Wayne

Moot now. I did the test, and you were mistaken. Cheers, Wayne

OK, I realized that I do have one handy, namely my little compact fan + toaster element (resistive heater) space heater, with a 2 prong plug and simple mechanical switches. When I turn the space heater to the medium setting, then I can measure across the 2 prongs of the plug to get the cold...

Ah, your assertion has changed. Originally it was that there would be no effect. I agree that my test doesn't show a big effect, but given the limitations it couldn't. Your new assertion may still be true, but you have presented no support for it. And we have some theoretical and...

That's not the lead. I didn't do the perfect experiment for the OP's original purposes, because I don't have a defective ground at the receptacle, but I did an experiment that disproves your assertion. So unless you've got something substantive to add, rather than repeating the same...

You're just wrong here. Did you not see this chart that summarizes it nicely? Cheers, Wayne

So, it occurred to me that at the risk of perhaps damaging my $40 DMM, I could do the experiment easily enough. At that bathroom receptacle previously mentioned, I first measured the N-G resistance while unloaded. The DMM only reads to 0.1 ohms, and the result was fluctuating between 0.1 and...

Right, but I illustrated how the ohmmeter measurement process could clearly be disrupted by a concurrent applied voltage, DC in this example. So if you are going to claim that in the OP's case it's not going to make a difference, it's going to take more than your simple assertion. I mean, you...

You are mistaken. See for example Voltage Ratings: 110/115/120, 220/230/240 or 440/460/480 for a nice explanation. Cheers, Wayne

To spell out mongo's last post, say the meter injects 0.2 mA DC as suggested, and you are measuring the resistance of a 400 ohm resistor. It will see (measure) 80 mV DC of voltage, do the math, and read 400 ohms on the display. Now suppose you take 10 of those resistors in series and hook them...

The 3% guideline is typically used for the branch circuit only. With a 2% allowance for a feeder and a 5% total allowance. [Unless I've reversed the 2% / 3%, which is possible.] Not an expert on the specs of a "typical" DMM, but I would certainly expect one to be able to distinguish between 0...

You can see from my example that last part is not correct. 50 ft of #12 is not a long circuit, and 10A is a very plausible current, and that gives you 1V of voltage difference. Double the length (still plausible at 100 ft) and increase the current to 15A (e.g. space heater or EVSE), and now...

That's not actually correct. N and G are bonded at the service disconnect and should not be bonded anywhere else (although they sometimes are by mistake). So obviously N and G have the same voltage at that bond point (it's a single point). Call that bond point the 0 voltage point. Then if you...

160A continuous load * 125% continuous use factor = 200A ampacity / OCPD size for non-100% rated OCPD. As to the wiring diagram, the schematic is in the upper right of the link you provided. Cheers, Wayne

That WEP4212 is a dual meter main, with space for one main breaker (up to 225A) for each meter. On the grid side of the meters is a 400A bus. The short answer should be that the 120% rule doesn't apply to that equipment. With a 200A breaker on each meter, you should be able to connect up to...

No, all the information you've presented is consist with the receptacle being the problem, and the feeder having a proper EGC via its conduit as expected. The #6 was for testing purposes only. Cheers, Wayne

There are some rules on GECs run exposed that require more protection in sizes smaller than #4 AWG, but that wouldn't apply to EGCs (normal grounds). This I don't know, but certainly doing it with the power shut off should give you a correct result. Cheers, Wayne

Only on the utility side of the service disconnect, or if the voltage to ground exceeds 250V. Taking a multimeter ohm reading between N and G at the 14-50 is a good way to start; if that's too high, then you can try chasing it upstream to see where the problem is. But if the multimeter shows...

As to the problem in the OP, my general understanding (not specific to Tesla's mobile connector) is that the EVSE is doing a ground assurance test, in which it intentionally tries to pass a small current from hot to ground. If it finds the ground resistance too high, then it fails the ground...

It's a "feature". The on-grid case is optimized for interconnection with a 200A main panel, which allows up to 32A of continuous inverter backfeed when using the 120% rule. Cheers, Wayne

That's what the PW+ data sheet says, 9.6 kVA full sun off-grid, but there's nothing saying that it can do that all from PV. That would be a PV plus ESS limit that the controller imposes due to the 50A breaker connection. The PV only limit may be lower and is unspecified on the spec sheet...

Whether a 200A feeder in the OP's situation would need to be 2/0 or 3/0 if Cu is an interesting question. [On other than a 200A residential service, or running between 90C connectors (like two Polaris connectors), a 200A feeder would always need to be 3/0 Cu.] But there's no reason that the...

By inverter I mean both PV inverters and the inverters built into each PW. Going by breaker size (which includes the 125% continuous use factor), you have 330A of inverters. 2 x 60A (PV) and 7 x 30A (PWs). Cheers, Wayne

Going back to the OP, if your final load calc comes out to 200A or less, and you are OK with limiting your total inverter capacity to 200A (via the GW CT-based feature), then I believe you can do what you propose without any new panels. Namely, you can set up a 200A feeder with the following...

It's clear that the letter of 230.83(A) allows you count the minisplits at 40%, as long as you are not adding any HVAC equipment. It's also clear that makes zero sense, as if you were to be adding HVAC, the existing minisplits would have to be counted at 100% under 230.83(B). So I'd be...

IIRC, the GW comes with a pair of CTs around the connection on one side of the relay. Some installations involve moving those CTs. But if you don't, then the GW automatically starts throttling inverters it controls if those CTs show net export in excess of 200A? And that's on top of the...

That works for the 400A panel, but a GW can only do one export control like that, I think? And with 330A of inverts on a 200A service, you'd need to use that export control feature to limit the grid export to 200A. Cheers, Wayne

I don't believe that's correct. My guess would be that the 0.79 ratio array might perform epsilon better. But for any practical purposes, they will perform the same. Cheers, Wayne

You can go ahead and take the RLA on the 3 smaller ones and subtract 25% of it (times 240V) from the load values for those units. Or cleaner presentation wise would be subtract 25% of the RLA for each unit, and then put in a separate line item for "25% of the largest motor" and put on that line...

So, on the load calc, the largest mini split condenser has an MCA of 32.5A, and for the other 3 you used MCA - 0.25 RLA, as discussed in the other thread? I'm a bit unclear on why NEC 230.83(A) doesn't split out the HVAC load and count it at 100% (like 230.82 and 230.83(B) do) but instead lumps...

Those figures reflect the unit's power draw at prescribed indoor/outdoor temperature combinations, and are not the figures to use for an NEC load calc. Cheers, Wayne