Low voltage short , what will happen ?

Thread Starter

t00t

Joined Jan 22, 2015
73
I have 2 (one positive one negative) bus bar carrying 5 VDC but at 500 amps.

What is going to happens if they happens to be accidentally short circuited.

Will it cause a huge explosion? Bigger or smaller then when you short a 230vac wires ?

I have short a few 230vac power supply cables before but at low amps . I am just figuring out what might happen if a low dc volt but high current power supply becomes short circuited.

Thanks
 

dl324

Joined Mar 30, 2015
10,734
You don't give sufficient information for us to give any meaningful answers.

5V at 500A can cause serious damage/harm. I saw someone short a 5V 100A supply with a metal watch band. He got a very serious burn. The power supply could put 70A into a short; which it did until the short was removed. The power supply tolerated the short better than the person, who learned the hard way why he should have followed the no jewelry policy...
 

danadak

Joined Mar 10, 2018
4,057
I would like to watch the event, from a mile away.

Fire for sure unless the supply is short circuit protected. Molten metal
spraying in many directions, could be a work of art. :)

Bigger or smaller then when you short a 230vac wires ?
Can't answer this w/o knowing more about the equipment, bus handling capability,
transformer ratings.....

Regards, Dana.
 

Thread Starter

t00t

Joined Jan 22, 2015
73
I would like to watch the event, from a mile away.

Fire for sure unless the supply is short circuit protected. Molten metal
spraying in many directions, could be a work of art. :)



Can't answer this w/o knowing more about the equipment, bus handling capability,
transformer ratings.....

Regards, Dana.

Thanks for the replies so far .

Basically it’s a chrome plating line . Where they use high current but low voltage to do the plating .

It has a circuit breaker for each bus bar . I am tasked to change a clamping plate for the bus bar . Problem is this clamping plate is in the middle of many live bus bars . And I cannot shut the power supply when I change the clamping plate because production is constantly going on.

Is there a formula or any guide lines as in how big an explosion or how much heat is created when short circuited ,given a specific voltage and current .
 

WBahn

Joined Mar 31, 2012
25,751
I have 2 (one positive one negative) bus bar carrying 5 VDC but at 500 amps.

What is going to happens if they happens to be accidentally short circuited.

Will it cause a huge explosion? Bigger or smaller then when you short a 230vac wires ?

I have short a few 230vac power supply cables before but at low amps . I am just figuring out what might happen if a low dc volt but high current power supply becomes short circuited.

Thanks
It very much depends on things you haven't told us.

If the DC supply is designed to detect and shut down under short circuit conditions, then it will shut down. Whether it does so before or after anything is damaged also depends on the design and on what is causing the short. A no-frills supply will output as much current as it can, probably well in excess of 500 A if that's what it's designed to operate up to, and it becomes of question of what the weak link is -- the supply or what is causing the short. If they both can take the max current the supply can deliver, then both will sit there looking stupid.

When I was working at NIST we used a 2 V supply capable of delivering 5000 A and we shorted it with superconductors all the time. But it was a constant-current supply so it would deliver whatever current we commanded (unless it required more than 2 V to do so). You could walk up to the exposed bus bars and short them with your hands and nothing would happen other then injecting noise into the measurement.
 
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