MEXICOWANDERER wrote:
IMHO Superb Post GDETrailer!
Down here transient voltages eat IC and discrete components like Nachos. They go on and on, 24/7 wearing down the p/n barriers. Electrolytic caps eventually talk to each other by smoke signals. Light off a microwave and eventually you will hear the Frankenstein "NYANNN ZOOOT" from the control board.
I tried to make it clear from the onset maybe I failed - my device does NOTHING to correct voltage irregularities lasting more than a few milli-seconds. That is a job for another type of device. But voltage correction devices are based on autoformer design which absolutely does ZIP as far as transients are concerned. An autoformer must have additional circuitry built in for it to do anything at all about transient voltage spikes. These spikes can be and are often positive, negative amplitude or BOTH oriented.
What is clearly different about what I build is the overkill redundancy of the MOV capacity and the TVS capacity. Both have finite lifetimes. Like having 64 shock absorbers. When a standard "surge suppressor" is throwing in the towel, my device is laughing. The last Tripplite box I tore into had every single MOV open circuit and both TVS diodes shorted. The GDT device, emphasis on singular was fine as it fluoresced at 210 volts.
I meant it when I wrote a worn out "surge protector" is like an empty fire extinguisher. False lying sense of security.
I cannot open up and examine every "surge protector" on the market. But I damned sure can tell you nothing affordable is going going to have six 20 mm MOVS (4) TVS and a pair of GDT, one from L1 to L0 the other from L1 to earth ground.
A direct lightning strike on a transmission line, enables relays to shunt the jolt to earth. Upstream and downstream to cut affected phase continuity and a third to earth the strike. A second's worth of interruption. DISTRIBUTION transformers are not auto transformers, so to a great degree they shunt power through L0 to earth ground. But obviously lots of runaway "joules" run down the line and hide in your precious electronics circuitry.
A strike on a powerline DISTRIBUTION circuit, the WYE connected 240 web down here is Armageddon for the entire line. I have seen 40Kw transformers ON FIRE jump their brackets and drag wires to the ground. Most people are too busy putting out fires in their home electrical to notice. The USA uses individual transformers for residences. Mexico uses much larger transformers that feed 240 volt four wire networks that can power 50 homes. All that network is exposed to lightning.
Unplugging is absolutely the best way to interrupt a lightning strike path. Down here a strike can occur two miles distant on a distribution network and it's time to pray.
To say lightning acts Quixotic may be the understatement of the century.
The sole hope is diversion...
IF an alternate path is presented to the pre-ionization feeler
THE post ionization feeler MAY choose the easier path
The nanosecond response time of the TVS diodes allows time to be bought.
Enough time for the MOVS to light off and burn out
And the GDT to delay long enough for a path to be decided upon.
Microseconds later the main pulse USUSALLY follows the trail of ionization and the pulse feeler.
To the easiest way.
Up the ground wire, and out the rig to L1 and the clouds.
Lots of if's but lots of undeniable successes. The best success a person can hope for is a disappeared service, vaporized shore power plug, utterly destroyed breaker box, and a hopefully small fire.
oI won't bother telling you what the alternative to this is like in an RV. A bad strike can dig a two foot deep trench, blast through foot thick solid concrete like it was paper, melt fifty feet of copper water pipe and blast out of the other side of the house. I've audited this type of damage with my own eyes (Tahoe National Forest Fallen Leaf Lake USFS station on the ridge) Not a tower. A ground single story facility. It happened in the early 70's. Anyone living up there should inquire with the USFS. It shows the power of lightning.
There EXIST good spike protectors. But none of them mate well with a recreational vehicle electrical circuit. BTW in hopes and prayer my circuit uses a 12 gauge earth ground conductor. Most RVs have 8 gauge ground circuits.
One can only hope. Thank God for individual RICE GRAIN fuses. It's stupid IMHO to have an individual fuse fail and fail the entire circuit.
Pianotuna writes “Hi Gde,
Do the ones you listed handle 30 amps and/or 50 amps?”
“Technically” in a “round about way” YES.
But not the way you would think of..
You are thinking of an external mystery box that you plug your RV into via the shore cord..
The devices I listed are power/surge strips in which you typically plug individual items into.. But the “protection” they offer actually EXTENDS to EVERYTHING on that power circuit provided the power strip is plugged into an outlet AND turned on AND the protection devices are functioning..
The devices which Mex mentioned are placed in PARALLEL to the “circuit” or power lines if you like.. They are not “In series” and therefore ALL the protection is available BEFORE AND AFTER where the protection devices are inserted into the circuit.
They work by SHUNTING voltages that exceed their breakdown voltage threshold TO GROUND, is also known as “clamping”.
To be very clear, NO “surge protection devices” can or will protect against a DIRECT LIGHTNING STRIKE even several miles down the power line!!! They only protect from lightning INDUCED surges (indirect lightning strikes)..
I am not aware of any device that would be reasonably priced that would handle a direct lightning strike, therefore the “best practice” of preventing damage during a strong thunderstorm is to physically disconnect your electronic devices from the power company (IE unplug shore power or TVs/entertainment items)..
A good explanation of MOVs can be found HERE
From the website above..
“The Metal Oxide Varistor or MOV is a voltage dependent, nonlinear device that provides excellent transient voltage suppression. The Metal Oxide Varistor is designed to protect various types of electronic devices and semiconductor elements from switching and induced lightning surges.
When exposed to high transient voltage, the MOV clamps voltage to a safe level. A metal oxide varistor absorbs potentially destructive energy and dissipates it as heat, thus protecting vulnerable circuit components and preventing system damage. Varistors can absorb part of a surge.
About the MOV – Metal Oxide Varistors
A MOV contains a ceramic mass of zinc oxide grains, in a matrix of other metal oxides (such as small amounts of bismuth, cobalt, manganese) sandwiched between two metal plates (the electrodes).
They can be connected in parallel for increased energy-handling capabilities.
MOVs can also be connected in series to provide higher voltage ratings or to provide voltage rating between the standard increments.
A Metal Oxide Varistor remains non-conductive as a shunt mode device during normal operation when voltage remains well below its “clamping voltage”. If a transient pulse (often measured in joules) is too high, the device may melt, burn, vaporize, or otherwise be damaged or destroyed.”
Typical simple in circuit usage (symbol with SIOV)..
Picture of MOV
Transit voltage bidirectional diodes and gas discharge tubes are also placed in parallel just the same as MOVs, they work similar to MOVs but with different speeds.
Cheap surge protection power strips ($8.99) typically only have MOVs and the more expensive versions ($30 and up) will have MOVs, Bidirectional diodes and gas discharge tubes.
When dealing with a 50A RV shore cord you simply need two surge strips and make sure that one of each is connected to L1 and L2..
One of the reasons as to why those external 30A and 50A “surge protectors” cost so much is the fact they ARE designed for the RV “industry” and they often offer other “protection” like OVER and UNDER voltage disconnect and or AVR (Automatic Voltage Regulation)..
To be clear Mexs idea does not address OVER/UNDER voltage nor does it address AVR..
If you dig around, you can find plug in surge/power strips which do have over/under voltage disconnect protection and if you want AVR many good UPS units actually provide surge AND AVR functions.. Just beware with these you must plug in items to be protected downstream to get the “protection”..
An additional way to add “surge protection” is to install a “whole house” surge protector in your RV breaker panel..
You can get a Leviton 51110-SRG Residential Surge protection Panel for as little as $43 from HERE
Looks like
Typical home installation requires the use of two 120V single pole breakers that go to the device.. In a RV you would need only one single pole 20A breaker for a 30A shore power connection and only need to wire L1 or L2 of the protector.. Or if no extra breaker spaces available you could simply wire to any of the breaker protected branch circuits in a pinch.
You can view the installation manual for the Leviton protector
HERE
Do the ones you listed handle 30 amps and/or 50 amps?”
“Technically” in a “round about way” YES.
But not the way you would think of..
You are thinking of an external mystery box that you plug your RV into via the shore cord..
The devices I listed are power/surge strips in which you typically plug individual items into.. But the “protection” they offer actually EXTENDS to EVERYTHING on that power circuit provided the power strip is plugged into an outlet AND turned on AND the protection devices are functioning..
The devices which Mex mentioned are placed in PARALLEL to the “circuit” or power lines if you like.. They are not “In series” and therefore ALL the protection is available BEFORE AND AFTER where the protection devices are inserted into the circuit.
They work by SHUNTING voltages that exceed their breakdown voltage threshold TO GROUND, is also known as “clamping”.
To be very clear, NO “surge protection devices” can or will protect against a DIRECT LIGHTNING STRIKE even several miles down the power line!!! They only protect from lightning INDUCED surges (indirect lightning strikes)..
I am not aware of any device that would be reasonably priced that would handle a direct lightning strike, therefore the “best practice” of preventing damage during a strong thunderstorm is to physically disconnect your electronic devices from the power company (IE unplug shore power or TVs/entertainment items)..
A good explanation of MOVs can be found HERE
From the website above..
“The Metal Oxide Varistor or MOV is a voltage dependent, nonlinear device that provides excellent transient voltage suppression. The Metal Oxide Varistor is designed to protect various types of electronic devices and semiconductor elements from switching and induced lightning surges.
When exposed to high transient voltage, the MOV clamps voltage to a safe level. A metal oxide varistor absorbs potentially destructive energy and dissipates it as heat, thus protecting vulnerable circuit components and preventing system damage. Varistors can absorb part of a surge.
About the MOV – Metal Oxide Varistors
A MOV contains a ceramic mass of zinc oxide grains, in a matrix of other metal oxides (such as small amounts of bismuth, cobalt, manganese) sandwiched between two metal plates (the electrodes).
They can be connected in parallel for increased energy-handling capabilities.
MOVs can also be connected in series to provide higher voltage ratings or to provide voltage rating between the standard increments.
A Metal Oxide Varistor remains non-conductive as a shunt mode device during normal operation when voltage remains well below its “clamping voltage”. If a transient pulse (often measured in joules) is too high, the device may melt, burn, vaporize, or otherwise be damaged or destroyed.”
Typical simple in circuit usage (symbol with SIOV)..
Picture of MOV
Transit voltage bidirectional diodes and gas discharge tubes are also placed in parallel just the same as MOVs, they work similar to MOVs but with different speeds.
Cheap surge protection power strips ($8.99) typically only have MOVs and the more expensive versions ($30 and up) will have MOVs, Bidirectional diodes and gas discharge tubes.
When dealing with a 50A RV shore cord you simply need two surge strips and make sure that one of each is connected to L1 and L2..
One of the reasons as to why those external 30A and 50A “surge protectors” cost so much is the fact they ARE designed for the RV “industry” and they often offer other “protection” like OVER and UNDER voltage disconnect and or AVR (Automatic Voltage Regulation)..
To be clear Mexs idea does not address OVER/UNDER voltage nor does it address AVR..
If you dig around, you can find plug in surge/power strips which do have over/under voltage disconnect protection and if you want AVR many good UPS units actually provide surge AND AVR functions.. Just beware with these you must plug in items to be protected downstream to get the “protection”..
An additional way to add “surge protection” is to install a “whole house” surge protector in your RV breaker panel..
You can get a Leviton 51110-SRG Residential Surge protection Panel for as little as $43 from HERE
Looks like
Typical home installation requires the use of two 120V single pole breakers that go to the device.. In a RV you would need only one single pole 20A breaker for a 30A shore power connection and only need to wire L1 or L2 of the protector.. Or if no extra breaker spaces available you could simply wire to any of the breaker protected branch circuits in a pinch.
You can view the installation manual for the Leviton protector
HERE
