10-30 Adapter Sold Out

[eprosenx]

I used #8 wire because it was available. I have conduit on both ends going in the attic and the run is only about 40 feet. I can always upgrade to #6 and 50A if ever needed in the future.

Oh btw, #8 THHN in conduit is rated for 50 amps (assuming you don't have to derate for temperature in the attic - though you get to use the 90c rating on the wire as your starting point for that deration if necessary). So you might be allowed to do a 50a breaker/circuit off that #8 awg anyway.

 

[jdcollins5]

Oh btw, #8 THHN in conduit is rated for 50 amps (assuming you don't have to derate for temperature in the attic - though you get to use the 90c rating on the wire as your starting point for that deration if necessary). So you might be allowed to do a 50a breaker/circuit off that #8 awg anyway.

Good point. I used Romex due to no conduit in attic.

 

[eprosenx]

Good point. I used Romex due to no conduit in attic.

Ahh, got it. So yeah, I read your previous message wrong. So yeah, you used the right size breaker then. ;-)

 

[bryan995]

Any idea when these will come back in stock at tesla?
EVSadapters says these are not identical to tesla supplied?
"A: Currently these adapters are made by us in Exeter, California, and are not the same adapters supplied by Tesla. I am not aware of any current recall though - could you provide me more information? "

https://www.evseadapters.com/pages/profile/39405

 

[blueangel3]

Any idea when these will come back in stock at tesla?
EVSadapters says these are not identical to tesla supplied?
"A: Currently these adapters are made by us in Exeter, California, and are not the same adapters supplied by Tesla. I am not aware of any current recall though - could you provide me more information? "

Hi Bryan,
Looks like jdcollins5 post #37 on Sept 6th mentioned that he received an email response from Tesla Shop:

“Our expected replenishment is overdue, but the target date for shipping is in the next couple of weeks”.

FYI

The 10-30 adapter is currently available at the Tesla Canadian shop site;
Model S/X/3 Gen 2 NEMA Adapters
However, seems like you can only have it shipped to a Canadian address and payment must be in 44 Canadian dollars.

Does anyone in the forum live in Canada and can help us order these adapters and help us relay/ship them to a US address for a reasonable fee? Please let us know, thanks.

 

[bryan995]

Hi Bryan,
Looks like jdcollins5 post #37 on Sept 6th mentioned that he received an email response from Tesla Shop:

“Our expected replenishment is overdue, but the target date for shipping is in the next couple of weeks”.

FYI

The 10-30 adapter is currently available at the Tesla Canadian shop site;
Model S/X/3 Gen 2 NEMA Adapters
However, seems like you can only have it shipped to a Canadian address and payment must be in 44 Canadian dollars.

Does anyone in the forum live in Canada and can help us order these adapters and help us relay/ship them to a US address for a reasonable fee? Please let us know, thanks.

Appreciate the response, will keep checking in for the replenishment ! Seeing that Canada now has them, it should hopefully not be much longer for the US.

 

[compu85]

We have an EVSE that's shared with our clothes dryer, which plugs into a 10-30. As others noted, the 10-30 is H-H-N, there is no ground connection.

However, because the EVSE and it's 14-30 connector is expecting a ground, when you hook the ground pin on the EVSE up to the neutral of the 10-30, it results in the car body being connected to neutral. Now this isn't immediately dangerous - neutral and ground are tied together in the electric panel. But if there was a neutral fault somewhere in the house wiring it would result in the car's body being live! And since the car sits on rubber tires, you could get a really nasty shock when you pulled the door handle.

I also found that the cabinet of our clothes dryer is tied to the neutral of the 10-30. We might be re-wiring this in the future...

-J

 

[jbcarioca]

My NEMA 10-30 adapter just arrived from Tesla a few minutes ago. i ordered it a couple weeks ago.

 

[eprosenx]

We have an EVSE that's shared with our clothes dryer, which plugs into a 10-30. As others noted, the 10-30 is H-H-N, there is no ground connection.

However, because the EVSE and it's 14-30 connector is expecting a ground, when you hook the ground pin on the EVSE up to the neutral of the 10-30, it results in the car body being connected to neutral. Now this isn't immediately dangerous - neutral and ground are tied together in the electric panel. But if there was a neutral fault somewhere in the house wiring it would result in the car's body being live! And since the car sits on rubber tires, you could get a really nasty shock when you pulled the door handle.

I also found that the cabinet of our clothes dryer is tied to the neutral of the 10-30. We might be re-wiring this in the future...

-J

Yes exactly!

Note that I have not 100% confirmed that the body of the Tesla is connected to the neutral pin on the 10-30 when connected in this way, but this is the assumption I am making (just like how your dryer is setup).

I think where this is particularly likely to have an issue is where your 10-30 is wired from a sub panel where neutral and ground are not connected together (they are only connected together back at the main service entrance panel). Say the neutral on the feeder cable from the main panel to the sub-panel comes undone. Then any 120v loads on the sub panel are indeed causing the neutral to have voltage on it in reference to ground, which you as a human could come across when touching your car and the ground at the same time.

No bueno.

We should test this. I have a 10-30 adapter, but I don't have a receptacle. I wonder if just plugging in my UMC with that adapter on it will let me test from the ground pin to the Tesla chassis. I would assume so since while the hots need to be engaged in the UMC, I would presume ground should NEVER be switched (in the UMC OR in the car itself).

 

[Eazyndn]

We have an EVSE that's shared with our clothes dryer, which plugs into a 10-30. As others noted, the 10-30 is H-H-N, there is no ground connection.

However, because the EVSE and it's 14-30 connector is expecting a ground, when you hook the ground pin on the EVSE up to the neutral of the 10-30, it results in the car body being connected to neutral. Now this isn't immediately dangerous - neutral and ground are tied together in the electric panel. But if there was a neutral fault somewhere in the house wiring it would result in the car's body being live! And since the car sits on rubber tires, you could get a really nasty shock when you pulled the door handle.

I also found that the cabinet of our clothes dryer is tied to the neutral of the 10-30. We might be re-wiring this in the future...

-J

I have been using this 10-30 adapter since I got the M3 2 months ago. Since our dryer uses gas, the electrical dryer outlet was not being used. The comments here seem to suggest it may be very unsafe? Can a few more experts chime in, please?

 

[brkaus]

I have been using this 10-30 adapter since I got the M3 2 months ago. Since our dryer uses gas, the electrical dryer outlet was not being used. The comments here seem to suggest it may be very unsafe? Can a few more experts chime in, please?

The 10-30 was allowed for a very long time -up to 1996. They are not as safe as a 14-50, but they are still allowed to remain in place. The corner cases look to me like they apply to poorly wired houses.

 

[Eno Deb]

I think where this is particularly likely to have an issue is where your 10-30 is wired from a sub panel where neutral and ground are not connected together (they are only connected together back at the main service entrance panel). Say the neutral on the feeder cable from the main panel to the sub-panel comes undone. Then any 120v loads on the sub panel are indeed causing the neutral to have voltage on it in reference to ground, which you as a human could come across when touching your car and the ground at the same time.

True, but the Tesla charger uses 240V (hot-hot) only, so there is no current on neutral. I don't really see a big risk. It's probably safer than many appliances with a 10-30 plug (which often have mixed 120/240V loads).

 

[Eazyndn]

The 10-30 was allowed for a very long time -up to 1996. They are not as safe as a 14-50, but they are still allowed to remain in place. The corner cases look to me like they apply to poorly wired houses.

Thanks.

 

[eprosenx]

I have been using this 10-30 adapter since I got the M3 2 months ago. Since our dryer uses gas, the electrical dryer outlet was not being used. The comments here seem to suggest it may be very unsafe? Can a few more experts chime in, please?

So I would check the actual wiring of that circuit to see if you perhaps could safely change from a 10-30 receptacle to a 14-30 receptacle (and buy the alternate Tesla adapter). I am pretty sure I could in my house since it was built in 92 but only has the 10-30 receptacle. All my wiring is romex, and I don’t think they made romex on 92 without a ground wire, so there is likely one hanging out unused in the electrical box. I keep meeting to check on this by removing the cover to my electrical panel (easier that moving my gas dryer).

I don’t think your situation is particularly dangerous (or else Tesla would not sell the adapter), but it is not what I would call optimal.

True, but the Tesla charger uses 240V (hot-hot) only, so there is no current on neutral. I don't really see a big risk. It's probably safer than many appliances with a 10-30 plug (which often have mixed 120/240V loads).

I agree that it is probably safer than some appliances since it has no 120v loads itself, but I still don’t particularly love the neutral line being tied to the Tesla chassis (making the untested assumption that this is true). Not to mention that it tests for a working ground (which in this case is the neutral) so if it was disconnected somewhere it is possible the UMC would discover that and fail to charge (but I am assuming that only the hot wires are switched by the EVSE contactor) and so the ground (neutral) in this case could be tied to the vehicle chassis even with the EVSE refusing to engage power.

 

[compu85]

Note that I have not 100% confirmed that the body of the Tesla is connected to the neutral pin on the 10-30 when connected in this way, but this is the assumption I am making (just like how your dryer is setup).

I did test this - I measured from the ground pin of an extension cord to the negative of the battery. Got just a few ohms. So the path was from my cord, back to the panel, through the neutral bond, through the dryer plug, through the EVSE, to the car body. So yes - when you use a 10-30 adapter you are connecting the car body to the neutral line!

Yes, the sub panel neutral fault is where this would be the most dangerous.

Some reading I did suggested the NEC allows jumping a ground from another nearby grounded outlet, to an ungrounded outlet to upgrade it. So changing out a 10-30 for a 14-30 might not require running new wire all the way back the panel.

 

[eprosenx]

I did test this - I measured from the ground pin of an extension cord to the negative of the battery. Got just a few ohms. So the path was from my cord, back to the panel, through the neutral bond, through the dryer plug, through the EVSE, to the car body. So yes - when you use a 10-30 adapter you are connecting the car body to the neutral line!

Yes, the sub panel neutral fault is where this would be the most dangerous.

Some reading I did suggested the NEC allows jumping a ground from another nearby grounded outlet, to an ungrounded outlet to upgrade it. So changing out a 10-30 for a 14-30 might not require running new wire all the way back the panel.

Interesting way to “upgrade” to have a real ground. It makes sense as ground is not normally current carrying.

Though you would need to ensure that other ground was of sufficient ampacity to flow enough daily current in order to trip the 30a breaker (I.E. is the ground in a common 20a circuit sufficient size for a 30a circuits needs?)

 

[CCIE]

...
Some reading I did suggested the NEC allows jumping a ground from another nearby grounded outlet, to an ungrounded outlet to upgrade it. So changing out a 10-30 for a 14-30 might not require running new wire all the way back the panel.

If your house is old enough to be using a 10-30 outlet, it's probably using BX cable (flexible metal shielding) and metal electrical boxes. If that's the case, then there likely already is a ground path via the metal box & BX. Changing to a 14-30 outlet and jumping its ground screw to the metal box would provide ground. Even if you have NM wiring ("romex"), there should be a ground conductor.

 

[eprosenx]

If your house is old enough to be using a 10-30 outlet, it's probably using BX cable (flexible metal shielding) and metal electrical boxes. If that's the case, then there likely already is a ground path via the metal box & BX. Changing to a 14-30 outlet and jumping its ground screw to the metal box would provide ground. Even if you have NM wiring ("romex"), there should be a ground conductor.

That is a good callout.

Question though: Is the old BX cable metal sheath rated for sufficient ampacity to provide that ground path?

I know that some of that corrugated armored cable requires a ground wire inside the armor in addition to the sheath.

While the sheath is probably better than nothing, I am not certain if it has enough ampacity at a low enough resistance level to provide a good fault current path in order to blow the breaker, etc...

 

[compu85]

Yes - wire size is important.

If your house is old enough to be using a 10-30 outlet, it's probably using BX cable (flexible metal shielding) and metal electrical boxes.

Good point - I'll have to check this out. I know there's BX going from the dryer plug to the fused disconnect nearby, and BX going out of the disconnect.

 

[CCIE]

That is a good callout.

Question though: Is the old BX cable metal sheath rated for sufficient ampacity to provide that ground path?

I know that some of that corrugated armored cable requires a ground wire inside the armor in addition to the sheath.

While the sheath is probably better than nothing, I am not certain if it has enough ampacity at a low enough resistance level to provide a good fault current path in order to blow the breaker, etc...

I’ve never seen a separate ground conductor within residential BX cable. The metal sheath is used as ground and should be of ample size to handle it.