What happens if you do too much VOLTS?

cupcake · March 2015

OK- if you do too much amps in a system it creates heat and a potential fire...

What happens if you add too much voltage to a system? Does the electricity jump through the conductor... like a spark plug?

--cakes

waynefromnscanada · March 2015

Yes, if the voltage is high enough, it can jump wire to wire or wire to ground, but you'd be looking at, depending on distance, a thousand or more volts. AND, this arc is also VERY capable of producing heat and a fire, especially with DC power! For instance, if you're familiar with oil furnaces, the ignition electrodes where the ignition arc occurs, is usually set at 1/8 inch apart and supplied with 10,000 volts for reliable ignition. Once the arc has commenced however, the gap can be widened to perhaps an inch or a bit more before the distance becomes too great for 10,000 volts to jump. BTW, in this case, the ignition transformer limits the current in the arc so no damage is done to the electrodes.
That said, if you're talking solar systems normally found around homes, by the time the voltage got that high, many failures of electronics will have occurred - - - - as in lightening damage.
BUT !!!!!!!! BUT !!!!!! BUT !!!!!!! Typical DC voltages found around solar systems can and will form an arc at quite low voltages if loose electrical connections are involved, AND FIRES CAN EASILY RESULT!!! DC voltages and AC voltages are very different in that with AC, the current stops flowing every time the voltage at the point of arc goes through zero and is thus relatively easily stopped, while with DC, once the arc is started, it's continuous, hard to stop, and thus VERY dangerous.

CALLD · March 2015

When it comes to smooth direct current high voltage can cause problems with switches or breakers because the arc doesn't self-extinguish as easily as with alternating current. This is because once an arc forms, the plasma channel becomes highly conductive. With AC the intermittent power allows time for the plasma to cool allowing the arc to extinguish sooner. With smooth DC like you get from solar panels or high voltage batteries the arc only extinguishes once it gets long enough to break the circuit. This can melt the switch contacts and everything around them. Usually this only becomes a serious concern above several hundred volts but has been observed with as little as 30volts in the right circumstances.

BB. · March 2015

More or less, you can get a "spark" with ~50 volts per 0.001 of an inch through air... And ~500 volts per 0.001 of an inch through typical insulation (clean/dry surfaces).

Of course, with excessive voltage you can get excessive current flow (12 VDC motor/lighting on 120 VAC).

With electronics (capacitors, transistors, integrated circuits), the actual distances between the various features can be much less than 0.001 of an inch. So an IC designed to run on 5 VDC may have an internal "arc or punch through" when connected to 12 VDC.

And with electronics, once there has been punch through--There is no self healing. And if the device does work, it will not be for long.

The excessive voltage does not have to be high current either. Just the static electricity of your clothes/shoes/carpet is more than enough to cause damage to IC's, and power FETs.

Many failure analysis results in the micro electronics industry where caused by excessive voltage (static electricity). That is why if you have ever been to a PCB assembler or IC mfg. company, they go through major effort to ground people, and use devices to "spray" ions in the air, metalized bags/foam, etc. to keep everyone/everything discharged relative go ground.

Of course, the details matter--What "excessive voltage" question do you have. About high battery voltage, high AC line, lightning, or what?

-Bill