I've been listening to you all talk of isolated vs non-isolated here and
I am trying to get my head wrapped around this issue. On the Manzanita
Micro charger, when I look at the AC plug, I see a grounding pin and 3
other blades. I assume that the unit is "grounded". On the recharging
end, I see a small Anderson connector and a green wire which I assume is
a grounding wire. If the unit is grounded, what is the danger or
dangerous act? For instance, if I assume I'm standing barefoot in the
proverbial puddle of water, and
1) if the pack is being recharged and the case is attached to the car
frame , what should I **not** touch? What can I touch and not be in
danger?
If I can't touch the car, then that **is** very very dangerous.
If I can't touch a battery terminal, then that is not as dangerous
but inherently dangerous when working on the car near a terminal.
2) If the charger is plugged in and **not** recharging, what is the danger?
On 6/15/2013 1:00 AM, Lee Hart wrote:
rustybkts wrote:
I have seen it mentioned before that the Manzanita chargers are not
isolated
from the mains.
As this is inherently very dangerous, I am surprised they are even
allowed
to be sold and have never heard of any non isolated power supply being
available in Europe.
Can anyone expand on how this can be allowed?
1. Regulatory standards are *voluntary* in most parts of the USA. Safety
agency listings like UL, ETL, etc. are not required by law, except in
a few places where local ordinances have been passed to require it.
(Two places I know of are Chicago IL and Los Angeles CA).
Thus, you can sell just about anything. The limiting factor is that
the seller can be SUED if the product causes damage or injury. Most
companies decide to get a safety agency listing (like UL or ETL) so
they can testify in court that their product has been tested and
met safety standards.
2. Non-isolated products are very common. Many consumer products leave
out isolation as a cost-cutting measure. Toasters, stoves, dryers,
air conditioners, and pretty much all high-power products are not
isolated.
However, there are safety standards that apply to such products.
The standards say that the case must be grounded, there must be
no possible way for a consumer to touch any of the potentially
"hot" wires coming from it, and it must have extra-strong insulation
between anything the consumer can touch and the AC line. Again,
complying with the standards is voluntary, though most manufacturers
follow them to avoid being bankrupt by lawsuits.
> A simple component failure will expose the output terminals to the
> mains supply.
Actually, the output terminals are *always* connected to the mains
supply. In effect, the charger is a bridge rectifier from the AC line
to the output terminals, plus a non-isolated buck/boost voltage
converter.
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