Posts: 2
Joined: Sun May 26, 2019 4:57 pm

50 amp outlet

Sun May 26, 2019 5:38 pm

I just bought a 13 FFE. Then I had an electrician install a nema 14-50 50 amp outlet in my garage. Figured it could do double duty usage between the car and an RV. Then I ordered Duosida Level 2, 32 amp EV Electric Vehicle Portable Car Charger from Walmart. I showed it to the electrician and he said that's not good and he needs to switch the 50 amp breaker to a 40 amp. He said it code to is the next level amp breaker, since it's a 32 amp charger, then you run a 40 amp breaker. But what I've read is 40 amp is the minimum, being 80% of the load, and 50 amp is fine. Any help and advice on this would be greatly appreciated. Thanks. ... ected=true
Last edited by nuttykev on Tue May 28, 2019 11:39 am, edited 1 time in total.

Posts: 71
Joined: Fri Nov 02, 2018 2:14 pm
Location: Belarus, Minsk
Contact: Website

Re: 50 amp outlet

Mon May 27, 2019 1:04 am

Ford Focus Electric consumes no more than 30 amps of alternating current during charging.
Usually it is about 29 amps.
A 40 amp breaker will be enough for you. I have done the same
I use translator. Sorry for the mistakes.

Posts: 52
Joined: Mon Oct 22, 2018 2:23 pm

Re: 50 amp outlet

Tue May 28, 2019 8:52 am

It should be ok to keep the 50 amp breaker for future proof. The EVSE will not pull more than 32 amp but down the road if you upgrade your EVSE and a new EV which can charge at 40 amp then you don't have to pay the electrician again to come out and switch the breaker.

Posts: 3
Joined: Fri Apr 28, 2017 1:59 pm

Re: 50 amp outlet

Tue May 28, 2019 10:21 am

Hi nuttykev

Because I cannot see the detailed electrical specifications about the Duosida charger, I can only guess. However, a common reason you for what your electrician is saying is that the electrical equipment you are trying to plug in is not approved for the breaker size. When I say that, the rating specifies which breaker size(s) the equipment can be safely used with - and that means only those sizes can be safely used. The rating is a UL or CSA rating, and that means that all of the testing (that should have been) done by whatever institution (that should have) tested the Duosida was done with that/those breaker size(s).

If I use a ridiculous example, it becomes more clear how having too large a breaker is even more unsafe than having a breaker that is too small. For example, if you used an adapter and plugged your vacuum cleaner into your 14-50 plug, then you would quite rightly say that it would never blow the breaker. But that is just the problem - if you develop a short in the vacuum, it will never blow that huge breaker because all of the conductors in the vacuum are too small and cannot conduct enough current to blow that breaker. And when that breaker does not blow, you get heat. And heat, followed by smoke and sometimes fire are the default problems when electricity goes wrong...

The same type of problem occurs with EVSEs that can limit their current. For example, I have a GE 30A EVSE that requires a 40A breaker, even though I can set it to limit to 24A (the safe current for a 30A breaker). The problem is that the EVSE has not been approved to limit the current to 32A by the safety agency, and thus you (legally) need the 40A breaker even if you never run the EVSE above 12A - the safe current for a 15A breaker. It does not mean the current limit does not work, it just means that GE has not obtained the approval for that mode of operation. Why not, you ask? Well, that is most likely because the 24/16/12A limits are provided by software, and because of that they would need to get their software approved. Getting software approved is a much more tricky thing to get done. The 30A limit is likely tested with the software disabled - if it is required at all.

In this case, it looks like the Duosida is sold with a 14-50 connector, which implies it is safety tested with a 50A breaker. However, an exception in the electrical code allows a 50A plug on a 40A circuit - because there is no such thing as a 40A plug. Therefore it is not clear and my hypothesis above may be completely off base. Thus - you need to check with your owner's manual or Duosida to see what breaker sizes they are approved for. If they are not approved, you need to consider if your insurance will pay for a fire caused by a piece of equipment that is not approved. Do not assume that just because something is for sale it is approved for use in the US or Canada - all equipment for sale in the US or Canada that plugs into the wall must have a mark from UL, CSA, or another safety agency such as ETL. There are no exceptions and that is one of the reasons your car does not plug directly into the wall - to do that auto makers would need to get the car approved by a safety agency - and that would be a real dog's breakfast. In addition, that mark must be genuine, not just something that someone printed on. The CE (Conformité Européenne) mark is what they use in Europe, and the suspiciously similar China Export mark is an example of what can happen.

For what it's worth, I believe that in Canada a homeowner is legally allowed to replace breakers, lighting fixtures, plugs, and switches themselves (IE they don't need an electrician), so you may be able to change that 40A breaker once the electrician is gone. But you need to check carefully your individual situation - since you might be planning to change that breaker size.

Hope that helps!

Posts: 2
Joined: Sun May 26, 2019 4:57 pm

Re: 50 amp outlet

Tue May 28, 2019 12:01 pm

Thanks for all of the info, especially PandH. That was a good read. I noticed the link wasn't working, so I fixed it. also, here is the info on the Walmart webpage where I bought it.

Charging plug meets SAE J1772 2010 standard and is UL approved #E364477
- EV Cord is UL approved #E344326
- Power plug meets NEMA 14-50 standard
- Control box meets SAE J1772 2010 control principle

I attempted to search those UL numbers, but nothing comes up, except other items for sale with the same numbers. My intention is to keep the 50 amp, for both rv usage and future proof with a newer EV at some point. So I need to know if this particular portable charge station is safe with a 50 amp outlet.

Again, thanks for the info and advise.

Posts: 409
Joined: Mon Jan 21, 2013 8:58 pm
Location: So Cal

Re: 50 amp outlet

Tue May 28, 2019 12:50 pm

My understanding is the breaker is to protect the home wiring, not necessarily the equipment attached to it. If the wire in the walls is rated for 50A, then the breaker will protect your wiring from burning up in the walls.

Now for the device you plug into the receptacle. I have an alarm clock that draws less than 1A plugged into a 15A receptacle and it is placed near my bed. Most appliances have fuses inside a point where the capabilities change. Now I'm speculating here. The cord on my clock that plugs into the wall is likely rated for greater than 15A, so if the cord frays and shorts, the cord will not burn up, but rather, trip the breaker it is attached to.

So shortly after where the cord goes into the clock, I'd expect to find a fuse. A fuse rated for less than the current required to cause damage. So no matter where there is a fault, my wiring and my home are protected.

I'd expect that the EVSE is also fuse fact, there are likely multiple. And like my clock, they are likely very near where the cord goes into the EVSE box. So the likely question is, what is the cord rated to? If something in the garage were to somehow tear into the cable and cause a short, what will happen first, the breaker trip or the cable catch fire? If it is a dead short, then I'd expect the breaker to trip quickly, but it is amazing how fast copper can burn.

This might not be to code in your area, but you could create a sub-panel at where you plug in the EVSE to handle the different current ratings. Or, you can find out if the EVSE is fused, and if so, replace the cord on the EVSE to be 50A capable.

One story: I was sitting in view of our dishwasher when a family member turned it on. Within a minute, I saw a flash that seemingly came from inside the appliance and smoke immediately followed. I quickly unplugged the appliance and noticed while doing so, a crackly noise coming from inside. The cord remained ok and the breaker never tripped. What had happened is the plastic door liner had warped and made contact with the back of the AC portion of the dishwasher's control circuit board. Although a very high resistant short at first, it eventually became less and less resistant and eventually created a short (low resistance) that cause the electrical traces on the internal circuit board to flash like a camera.

The moral of the story is that things go wrong from time to time and without warning. The manufacturer likely designs for best practice while maintaining low cost. I'm positive my dishwasher doesn't draw 15A, but I'm glad the cord was rated for 15A else that may have "flashed" too. I'd recommend following the recommendations from the manufacturer.

Posts: 1139
Joined: Tue Aug 16, 2011 11:40 am
Location: Toledo, Ohio

Re: 50 amp outlet

Tue May 28, 2019 7:26 pm

Your electrician is an idiot. I wouldn't let him touch anything further in your house. If he installed a NEMA 14-50 receptacle to code, a 50A circuit breaker is appropriate. As stated above the circuit breaker is to protect your house from burning down. It should not exceed the ampacity of the wires or receptacle that it supplies.
2014 Blue Candy FFE (since this forum doesn't allow BBcode in sigs)

Posts: 4
Joined: Tue Jul 28, 2020 11:59 pm
Location: Virginia Ashburn

Re: 50 amp outlet

Mon Sep 14, 2020 4:54 am

Well, in your case the best way to fix the problem is to find another qualified specialist which will help you for sure. One of my friends had a similar situation, and he had contacted st louis electrician which are specialized in almost everything if it is related to electricity. He called them, and in one day they were on his place already working. It took about 2 hours and after that everything was nice. I am sure you will be pleased too with their services.

Return to “Batteries and Charging Forum”