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gozer

Well-known member
Leaf Supporting Member
Joined
Apr 15, 2024
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94
I am the owner of an old house that has a maxed out breaker box and I'd like (need) to hook up an evse to my dryer outlet. Its the 3 prong type of outlet. What I want is a 'smart switch' that will let me charge at night, then when the dryer is needed it will automaticlly switch over and power the dryer with no input from my wife/ daughter. Has anyone had experience doing this? recommendations? Thnks.
 
May be time to assess what you have vs what you need. If the service is maxed out with the loads you have, that is one thing, but if you have no more breaker spaces, it is often easy and cheap to add a sub panel and install more breakers in the sub panel.
Old driers plugs are 10-30 120/240 with no dedicated ground. Not the best for charging a car.
If it were I, I'd be looking for a permanent solution and not trying to "get by". Sooner or later that will bite ya. The automatic part is going to be the trouble.
 
Here's what I did in my garage to provide empty breaker spots for a 240vac outlet.

In the Breaker Panel combine two existing circuits into one 15-amp breaker. This provides an empty breaker spot.

Choose two existing circuits 15 amp circuits.​
Verify the combined power draw of both circuits is within the limits of one 15-amp breaker.​
Inside the Breaker Panel, combine two black hot wires using a WAGO wire connecter to a third black wire pigtail.​
Connect that third black wire to the breaker.​
Now free up a second circuit breaker slot, as you're installing a 240vac tandem breaker.​
This may clarify:​
 
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Depending on locale there are also dual breakers, two 15 amp breakers that take a single slot on the panel.
Doubling wire in the breaker itself may or may not be permitted. Some breakers permit two wires. Some do not and some locale’s may not approve such connections.
 
I don't think it's as much of a locale issue as it is the panel supporting tandem (or half size) breakers. Some GE Homeline panels which are fairly popular only support 1" breakers. The pigtail method for combining branches is a must. Two wires in a breaker clamp (or in the neutral bus bar clamp) is not up to code. Wago are easier but simply pigtailing with a regular a wire nut sized for 3 14awg wires is sufficient and less costly.
 
Depends on the breaker, if it is allowed by the factory, and local code, you can. QO Square D's allow two wire on the breaker. Many others do not.
If you look how Square D clamps the cable on the breaker, you see it can handle one wire on each side of the securement screw. Somewhere in there lit I found it in writing that it was allow if ok with local code.
 
I don't think it's as much of a locale issue as it is the panel supporting tandem (or half size) breakers. Some GE Homeline panels which are fairly popular only support 1" breakers. The pigtail method for combining branches is a must. Two wires in a breaker clamp (or in the neutral bus bar clamp) is not up to code. Wago are easier but simply pigtailing with a regular a wire nut sized for 3 14awg wires is sufficient and less costly.
Again, depends on local code. Some don't allow pigtailing in breaker box from what I have read.
There are options but check your local code 1st.
2 wires in a breaker that is designed for it and acceptable to local code is both neat and safe.
It is not true to say it isn't to code. Neither two wires in a breaker nor pigtailing in the breaker box is ALWAYS to code.
 
Got curious, and went out and looked at a Sqaure D QO breaker.
Clearly marked near the terminal, 1 or 2 conductors, CU or AL 8 to 14 ga.
Just because the Mfg allows it doesn't mean the local inspector will, but if the Mfg doesn't the local will not either!
The Cutler-Hammer breakers are NOT marked for more than one conductor.
 
May be time to assess what you have vs what you need. If the service is maxed out with the loads you have, that is one thing, but if you have no more breaker spaces, it is often easy and cheap to add a sub panel and install more breakers in the sub panel.
Old driers plugs are 10-30 120/240 with no dedicated ground. Not the best for charging a car.
If it were I, I'd be looking for a permanent solution and not trying to "get by". Sooner or later that will bite ya. The automatic part is going to be the trouble.
Just for the record -- a 10-30 dryer plug is most certainly grounded. What it lacks is a neutral. And for nearly all 240v EVSE that are hardwired (to the best of my knowledge) a neutral wire is not needed. The problem with using that circuit however, is that per most recent code, you should have a GFI breaker for an EVSE that is NOT hardwired. And since you obviously are planning some sort of dual use set-up, the EVSE will not be hardwired.

And a GFCI breaker needs the neutral *I think*. At least I have never wired one up without the Neutral. I think it would detect the neutral fault and blow.

Now, there are tons of EVSE with plugs and people running them on circuits without GFCI. If you are NOT stupid and try to unplug something that is under a load, you are fine. Code is requiring GFCI because so many people assume its safe to just pull a plug out to stop something. Well that's fine with a 120v circuit, but a 240v circuit under a heavy load will arc.
 
No, a NEMA 10-30 Has a neutral but no dedicated ground. While it is true that neutral and ground are eventually connected at the bonding point, there is a difference. The center of the "crows foot" on a 10-30 may carry 120 volt loads between it and one of the "hot" wires. No current is permitted to be carried on a "ground".
If you look on a NEMA 10-30 device, it will be labeled 120-240 volt. This applies to all "10" series outlets.
A NEMA 6-30 is almost the same, except it only has two hots and ground and should only be connected to 240 volt loads. The difference between the two types (10-30 and 6-30) is what the "third wire" is there for.
Two pole GFI's breakers 50 amps and below have a neutral connection and can be used on circuits with both 240 and 120 volt loads on the breaker. 60 amp and above generally are 240 volt only GFI.
The NEMA 10 series are obsolete and only still exist to service existing installs. New "driers" and wiring for them should be 14-30 or if no 120 volt loads 6-30 can be used.

https://www.americord.com/nema-char...VINH-Apro0ngbuvr1uFytV7vSi_hbP5TLiqjAMMcVBoug

And another quote explaining the history:
21

NEMA 10 connectors are ungrounded, 125/250V connectors which have been outlawed since 1966 when grounding came in.
Because of appliance industry lobbying, exception was made until 1996 for ranges and dryers only. So we are dealing with really ancient codes here. The exception required that electrical wiring be 4-wire as soon as old stocks of ungrounded cable were used up*, but that the legacy NEMA 10 connectors could be used for ranges and dryers only.
The idea was that by about 1970, legacy stocks of 3-wire cable would be gone, and all cabling would provide 4 wires, and a person with a NEMA 10 connector could simply remove the connector and find a 4-wire connection fit for a NEMA 14.
 
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And a GFCI breaker needs the neutral *I think*. At least I have never wired one up without the Neutral. I think it would detect the neutral fault and blow.
They won't detect current loss to the neutral because as you noted many 240V receptacles have no neutral, but they must have a ground and a GFCI breaker will detect a leak to ground. So they are still effective without a neutral. Years ago it was claimed that the ground check that an EVSE does to determine it has a ground or not was tripping GFCI breakers. Perhaps the check was modified to use lower current to test since I don't see this reported more recently. The EVSE must see a ground to be operative.
 
The lit I have on tandem (240 volt) GFI breakers show that both legs have a current sensor to neutral but counter wound to each other. On circuits where 120 volts is used to the neutral, the GFI looks at power out and power back to the neutral and trips if they don't match.
on 240 volt load they compare power out on both legs and trip if they don't match. They will not trip if the small leakage is matched on both legs, they just "see it" as a load, but that condition is highly unlikely to happen.
So GFI C/B can be used on both 240 volt and 120 volt loads on the same breaker, but you must connect the returning neutral line to the breaker. If you don't it will trip on any 120 volt load.
You can leave the neutral off if the loads are only 240 volt and NEMA 6 series outlets are used and it will work. No real advantage to that some might as well connect it. (2 wire + ground). Any 14 series NEMA on the line and you must used the neutral connection on the breaker.
 
Splicing is not allowed in a panel in Canada under CEC. It is OK in the US under the NEC where splices are allowable. (NEC 312.8). Crimps may not be approved but wire nuts are ok.

You can find online readily of complaints of the EVSE doing a ground check and tripped their GFCI breakers. I probably explained why it's happening wrong, but it has happened in the past. I suppose the EVSE outlet was miswired and is why this was happening?

It makes sense that 240 GFCI measures current differential of both legs. I should have realized that because 120V GFCI's do so as well. My house is ungrounded and the "fix" was to put a GFCI outlet on the first outlet of each branch, which I did. And found a hijacked neutral in a light fixture that blew the branch GFCI whenever a different ceiling light was turned on. That was tough to find. I had to run a wire from the fixture with the light being controlled to the fixture which was not controlled but from which the neutral was taken. That's not code compliant either, but I guess it's the lessor of 2 evils. Rewiring that branch would have been very difficult because it also fed outlets in 2 other rooms. Anything I redid or added in my house I of course used grounding.
 
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