New Chinese charger with no ground?

[ironhalo]

Just got a new 72V 10A Chinese made (generic, no name) charger. Apparently when they ship with an American 110V plug they omit the ground wire?

Obviously there is a ground pin on the board (though not sure why it’s labeled “N”). Any reason why i should not immediately replace this power cable with a proper grounded one?

 

[ironhalo]

So continuity testing reveals that the extra pin on the board I thought was a ground pin is not connected to anything at all. Including the chassis. Is this normal? Do these types of chargers typically not have a ground?? Seems crazy for something that could short circuit and start a fire to not be grounded.

 

[dose0018@umn.edu]

so you're referring to 2 vs 3 prong cord right?
If so I have two 36v chargers both sold and shipped by reputable US companies (Idk where they are actually made) that both have two prong charger cords.

 

[john61ct]

Relying on the chassis being 100% insulated from current forever.

Check the UL certification, if not valid, illegal to import.

 

[ironhalo]

so you're referring to 2 vs 3 prong cord right?
If so I have two 36v chargers both sold and shipped by reputable US companies (Idk where they are actually made) that both have two prong charger cords.

Correct, the third prong being ground. Interesting, every other LiPo charger I own has a ground wire, and they are all far lower voltage AND amperage than this one.

 

[Tony01]

It’s fine, it’s AC, it doesn’t matter how you plug it in.

 

[kdog]

2 wire appliances are spored to be double insulated, so normally they have a plastic shell. The smaller fanless plastic chargers don't require a ground bc the outside can't be live.
All metal shell appliances should have a ground. I cant think of any metal based appliances in my house (ebike related or not) that have no ground. Even the DC output at 84v could be dangerous in the right (wrong?) situation.
What to do though... I don't know enough about electronics to be able to definitively say, but I'd be sticking a new plug on it, grounding the chassis and isolating it at the same time. Maybe wait until someone responds who is more certain than I.

 

[LeftieBiker]

With an all metal chassis yes, I would ground it. I have similar chargers and they are all grounded. Only the ones with plastic housings are not grounded.

 

[eMark]

Just got a new 72V 10A Chinese made (generic, no name) charger. Apparently when they ship with an American 110V plug they omit the ground wire?

A charger that size in a metal enclosure should be wired for a 3-prong ground plug. Even my 2.5a plastic case charger has a 3-prong ground plug.

You should remove the existing AC plug and replace with a 2-prong plug that has that wider prong wired to negative side. If the existing plug has a wider negative prong you should be OK ... assuming whatever electrical outlet you use is correctly wired (easy enuf to check with multimeter).

John is correct that it isn't UL approved so you need to contact the supplier as they're probably not aware.

 

[dose0018@umn.edu]

I would be surprised that the suppler is unaware, more likely do not care.

 

[eMark]

I would be surprised that the suppler is unaware, more likely do not care.

Not necessarily! Maybe the supplier is unaware or is just waiting to see if anyone complains. If it was purchased through Amazon they would want to be informed. If Amazon they should definitely be informed that it isn't UL Approved and why the charger (metal enclosure) definitely needs a 3-prong plug.

From the photo it looks like that plug doesn't even have a wider negative prong side. The Chinese manufacturer should have known better and done better by at least having a plug with a wider negative side prong.

 

[dose0018@umn.edu]

well, it is great if they do care and want to improve. It just does not mesh with my Aliexpress experiences.

 

[LeftieBiker]

From the photo it looks like that plug doesn't even have a wider negative prong side.

Just for clarity: the prong that isn't the small Hot one is the "Neutral" wire, not the "negative." In AC circuits the polarity switches multiple times every second.

 

[ironhalo]

It’s fine, it’s AC, it doesn’t matter how you plug it in.

You're referring to polarization (skinny prong vs. fat prong). I'm referring to a ground wire (third round prong)...which to my knowledge all high amperage and/or metal encased devices are supposed to have in the US. Clearly they have bypassed any sort of import screening for that, which I'm sure is relatively easy to do, especially right now.

 

[eMark]

From the photo it looks like that plug doesn't even have a wider negative prong side.

Just for clarity: the prong that isn't the small Hot one is the "Neutral" wire, not the "negative." In AC circuits the polarity switches multiple times every second.

If that's the case then why when checking an electrical output that's accidentally reverse wired (whether AC or DC) a multimeter will indicate a minus sign (negative). Besides if the hot wire is "positive" then the other wire is "negative" (whether AC or DC).

Have you never seen a wiring diagram (whether AC or DC) showing the + (plus side) and the - (negative side). With 3 wires (AC) it's the green ground wire that is "neutral" unless somebody "crossed his wires" :wink:

 

[LeftieBiker]

From the photo it looks like that plug doesn't even have a wider negative prong side.

Just for clarity: the prong that isn't the small Hot one is the "Neutral" wire, not the "negative." In AC circuits the polarity switches multiple times every second.

If that's the case then why when checking an electrical output that's accidentally reverse wired (whether AC or DC) a multimeter will indicate a minus sign (negative). Besides if the hot wire is "positive" then the other wire is "negative" (whether AC or DC).

Have you never seen a wiring diagram (whether AC or DC) showing the + (plus side) and the - (negative side). With 3 wires (AC) it's the green ground wire that is "neutral" unless somebody "crossed his wires" :wink:

I don't know why a multimeter will do that. I just know that in AC 120 volt circuits one wire is the Hot and the other is the Neutral. The Hot wire is connected to the overhead (usually) cable from the power company, while the neutral is bonded to ground at the main panel. The means that when the circuit is completed it involves current flowing through all of the land (ground) between the house and the power generator. Positive and negative are meaningless in AC circuits, though, because as the generator spins the polarity changes with each cycle - usually 120 times per second with 60 hertz AC. This is why it is called "alternating" current.

 

[Matador]

Even if you reverse polarity of the AC, the bridge rectifier will still give you positive DC.

Matador