Reverse polarity at pedestal

[meganjoe]

I always thought Reverse Polarity is when the Black Hot Wire(in this case 120 volts ) is reversed with the White Neutral Wire.. I believe an overloaded neutral is a separate issue.

What Happens When Polarity is Reversed at a Receptacle?

Most electrical appliances and devices are designed so that their "on-off" switch interrupts electrical power at the point of entry into the appliance or device circuitry or components. If you switch the hot and neutral wires that may not quite be the case, and parts of the device will remain energized or potentially energized even when the electrical device switch is OFF. No electrical current may flow, but it could flow if someone touches the wrong part of the device, or damage may be caused in other circumstances as well, as we describe next.

Found this explanation online:


Watch out: Reversed polarity on an electrical outlet is dangerous. If you accidentally reverse these wires the device you plug in to the receptacle may "work" but it is unsafe and risks a short circuit, shock, or fire.

Joe

[Papa GLS]

[B and B]

Originally Posted by Myrle

Not good for LED lights and some electronic devices.

Do you have a source for this? Most LED lights in a RV are 12 volt.I do not know of a single TV, cell phone or computer power supply. that could care about reverse polarity.

The only thing reverse polarity can cause is hot skin if the RV has a bad ground and the ground and neutral are boned at the RV service entrance that is Illegal, against code and RVIA quality sticker as inspected annually.

[westom]

Originally Posted by meganjoe

Watch out: Reversed polarity on an electrical outlet is dangerous. If you accidentally reverse these wires the device you plug in to the receptacle may "work" but it is unsafe and risks a short circuit, shock, or fire.

Polarity is one of many protection layers. Reverse polarity is dangerous like parking a car only with a transmission in park. As if that tiny pin will always hold a car. (A lady in the next town was killed because she did that.) Informed drivers also use the parking brake.

Polarity is an equivalent of a parking brake. Other circuits should also make reverse polarity irrelevant. But failures happen. Failures rarely happen. But that is never an excuse to ignore a defect. Engineers put polarity in for good reason.

[meganjoe]

Originally Posted by westom

Polarity is one of many protection layers. Reverse polarity is dangerous like parking a car only with a transmission in park. As if that tiny pin will always hold a car. (A lady in the next town was killed because she did that.) Informed drivers also use the parking brake.

Polarity is an equivalent of a parking brake. Other circuits should also make reverse polarity irrelevant. But failures happen. Failures rarely happen. But that is never an excuse to ignore a defect. Engineers put polarity in for good reason.

Not sure what you mean when you say"Other Circuits should also make reverse polarity irrelevant".. If the power at the pedestal is reversed won't that affect all 120 volt ckts. in the camper??

Joe

[Papa GLS]

Read posts #10 & #21!!!!!! It is very simply & correctly explained.

[westom]

Originally Posted by meganjoe

If the power at the pedestal is reversed won't that affect all 120 volt ckts. in the camper??

Voltage on a black wire is positive when voltage on the white wire is negative. Then voltage on a black wire is negative when voltage on the white wire is positive. This happens 60 times every second. If wires are reversed, then what in those two sentences changes? Nothing. Polarity is irrelevant to how an appliance operates. Again, polarity is simply another protection layer for human safety.

Be wary of most who make recommendations (ie polarity causes appliance damage) when reasons why are never provided. Junk science would almost disappear if we held others to that standard. And also demand numbers. Most of us never demand that standard making scams so easy to promote.

"Other circuits" define many concepts including galvanic isolation. Even internal filters are designed so that polarity reversal is irrelevant.

[Papa GLS]

Well meganjoe & Brewhedd, what more can we say?
I'm done.

[meganjoe]

Originally Posted by westom

Voltage on a black wire is positive when voltage on the white wire is negative. Then voltage on a black wire is negative when voltage on the white wire is positive. This happens 60 times every second. If wires are reversed, then what in those two sentences changes? Nothing. Polarity is irrelevant to how an appliance operates. Again, polarity is simply another protection layer for human safety.

Be wary of most who make recommendations (ie polarity causes appliance damage) when reasons why are never provided. Junk science would almost disappear if we held others to that standard. And also demand numbers. Most of us never demand that standard making scams so easy to promote.

"Other circuits" define many concepts including galvanic isolation. Even internal filters are designed so that polarity reversal is irrelevant.

So why are plugs designed to only be plugged in to a receptacle one way??

Joe

[westom]

Originally Posted by meganjoe

So why are plugs designed to only be plugged in to a receptacle one way??

That was answered repeatedly - for human safety. One of many human protection layers.

[MarsMan]

I wish I knew more- still learning

[meganjoe]

Originally Posted by westom

That was answered repeatedly - for human safety. One of many human protection layers.

No.. Not just for human safety..

Also found this explanation online..

"Some appliances and electronic devices may be damaged if polarity is reversed

Some appliances and some electronic equipment may be damaged if left connected to a reversed-polarity electrical circuit.

We disassembled a coffee maker that had burned-up and found that the appliance had been damaged by being left connected to its receptacle with polarity reversed. The presence of live voltage at the "wrong end" of a circuit or circuit board may cause some devices on the board to remain energized even when the device has been "switched off". A result can be overheating or electrical shock hazards."

Joe

[westom]

Originally Posted by meganjoe

Also found this explanation online..
"Some appliances and electronic devices may be damaged if polarity is reversed

Which part in a coffee maker was damaged? Why would reverse polarity damage it? Just because you saw damage does not mean polarity was relevant. I have done this stuff professionally for 40 years. Suddenly everything I knew was wrong because someone posted something on the internet - without even one reason that says why?

It was on the internet - so it must be true. Classic junk science reasoning.

Multiple posters noted reverse polarity does not cause appliance damage. Even posted were some reasons why including galvanic isolation and filters intentionally designed to work with every polarity. Even made obvious by "black wire + when white wire -" and "black wire - when white wire +". Why ignore that? If reverse polarity causes damage, then AC cannot exist. Because polarity is constantly normal and reversed 60 times every second.

Conclusions only from observation are classic junk science reasoning. That quoted poster has no electrical knowledge - as demosntrated by the missing reasons why. Same logic also proved smoking cigarettes increases health. Why do you let them brainwash you. Every part in the coffer maker sees normal and reversed polarity 60 times every second. So every coffee maker must be damaged when connected to AC mains - using his reasoning.

[OldCoot]

As westom stated, also years ago the electricians didn't pay much attention to which wire went on which side of an outlet. Only in the last few years since they came out with the wide tang plugs for making sure the appliance was plugged in properly for the grounding to be proper. Hot on the gold(wide tang socket), neutral on the silver and ground on the green.

[fonzie]

Originally Posted by OldCoot

As westom stated, also years ago the electricians didn't pay much attention to which wire went on which side of an outlet. Only in the last few years since they came out with the wide tang plugs for making sure the appliance was plugged in properly for the grounding to be proper. Hot on the gold(wide tang socket), neutral on the silver and ground on the green.

Tiny correction:

Hot on the gold(small tang socket), neutral on the silver (wide tang socket) and ground on the green.

[Brewhedd]

Reverse polarity has the potential to cause damage and is a safety issue. By the way the frequency is 60 hertz or cycles per second meaning the polarity is reversed 60 times a second not 120. As stated previously reverse polarity is the when the hot and neutral are reversed. Here's the problem- Most electrical appliances and devices are designed so that their "on-off" switch interrupts electrical power at the point of entry into the appliance or device circuitry components. If you switch the hot and neutral wires that may not quite be the case and parts of the device will remain energized even when the switch is OFF. No electrical current may flow, but it could flow if someone touches the wrong part of the device.

[OldCoot]

Originally Posted by fonzie

Tiny correction:

Hot on the gold(small tang socket), neutral on the silver (wide tang socket) and ground on the green.

I stand corrected, CRS and too lazy to look at a receptacle. Thanks!

[OldCoot]

I would wager that there are a lot of older homes that are not wired for the new appliances with respect to hot & neutral wiring on the receptacles. A lot don't even have the narrow/wide receptacles.

[westom]

Originally Posted by OldCoot

I would wager that there are a lot of older homes that are not wired for the new appliances with respect to hot & neutral wiring on the receptacles. A lot don't even have the narrow/wide receptacles.

And all appliances must work just fine on all wiring from 1930 till today.

Again, polarity is only for human protection; is irrelevant to appliance protection. Other features that provide human safety protection layers include galvanic isolation, double insulated, safety ground, circuit breakers, arc fault breakers, and GFCIs. Also for human protection; not for appliance protection.

Back to the original topic - what is measured to determine polarity reversal might also detect completely different anomalies. Those other anomalies would explain why 'reverse polarity' appears to come and go. To say more (that is not wild speculation) requires voltage numbers from a meter.

[meganjoe]

Does a product work if reverse polarity exists? The short answer is yes, but the plug configuration now bypasses safety mechanisms that would normally protect the product from potentially becoming dangerous. What is bypassed is the fuse in the appliance designed for the hot source is now on the neutral side; if a power surge travels to the outlet or product, the fuse can interrupt the electricity and protect the electrical components thereby avoiding the potential for a fire.

Joe