Home AC Welder Breaker ???

[k0ua]

Well he knows the error of his ways now with 3 of us telling him the same thing

James K0UA

 

[joshuabardwell]

Welder shouldn't make any more spikes on the lines than the dryer or fridge turning on and off. But if you want to you could add a hole house surge supressor to the panel when you add the breaker.

Dan,

My understanding is that whole-house suppressors (such as the kind that attach behind the meter) protect the house from surges coming in from the outside. I don't see how they would protect something inside the house from something else inside the house that was making a surge. IMO, the safest thing to do is to put whatever appliances you are concerned about onto a surge suppressor, and then it doesn't matter where the surge is coming from, you're protected.

As a side note on this topic: all surge suppressors that a typical consumer is going to encounter are consumable. What this means is that, after so many surges, the suppressor loses the ability to protect. This is what the joules rating indicates. The higher the joules rating, the more surges the suppressor can absorb before it is worn out. Here's the kicker: some surge suppressors--mostly the cheap ones--don't give any indication that they have used up their protection. They just keep on working, with you none the wiser. So when you go shopping for a surge suppressor, make sure to get one with a "protecting" light that goes out when the suppressor is used up. Better, yet, get one that simply cuts the power once it is no longer able to protect the equipment. That way, you are guaranteed never to be in a state where you're un-protected and don't know it.

 

[CNC Dan]

Dan,

My understanding is that whole-house suppressors (such as the kind that attach behind the meter) protect the house from surges coming in from the outside. I don't see how they would protect something inside the house from something else inside the house that was making a surge.

think of it as a pressure relief valve in the middle of a hose.

doesn't matter if the overpressure comes from either end, as long as it opens.

 

[k0ua]

Joshua, the whole house surge arrester will do some good for internally generated spikes also, as it is on the "buss". Current does not run thru the device, it is a "clamping device " it sits on the voltage buss and starts to conduct when the spikes rise above its conduction threshold. It does not "know" where the spike comes from, either the line or load side. There are other factors in play here like the propagation time of the wave fronts from the downstream device thru the media (the copper wire) but to get to another circuit the spike is going to have to come up the wire to the common point and the arrester will be waiting for it and clamp it to a preset level (provided it is still working ) and provided it can handle the energy in the transient. I agree that they are a "finite use device" in that they will only take so many hits and usually fail open and useless. If a whole house device were to fail shorted it would either pop the main service breaker or go up in smoke pretty quick and become open.

James K0UA

 

[joshuabardwell]

I think I see what y'all are getting at. The surge suppressor is not directional. Whenever voltage rises above the threshold, it opens and shunts to ground. The only potential for interference between devices inside the house is if they were on the same breaker, and even then, there would be a relatively short window (like, some fraction of the speed of light times the length of the wire) until the voltage reached the suppressor and was shunted. In the case of a welder, which is essentially always going to be on an isolated breaker from the rest of the house, a whole-house surge suppressor will always protect the house, because nothing else is going to be on the circuit with the breaker.

 

[k0ua]

I think I see what y'all are getting at. The surge suppressor is not directional. Whenever voltage rises above the threshold, it opens and shunts to ground. The only potential for interference between devices inside the house is if they were on the same breaker, and even then, there would be a relatively short window (like, some fraction of the speed of light times the length of the wire) until the voltage reached the suppressor and was shunted. In the case of a welder, which is essentially always going to be on an isolated breaker from the rest of the house, a whole-house surge suppressor will always protect the house, because nothing else is going to be on the circuit with the breaker.

Thats pretty much it, except the suppressor does not Open and then shunt to ground, it is across the line at all times and just clamps when the voltage spike rises above its clamp voltage.

James K0UA

 

[joshuabardwell]

Thats pretty much it, except the suppressor does not Open and then shunt to ground, it is across the line at all times and just clamps when the voltage spike rises above its clamp voltage.

Hm. I guess I was thinking of it being like a lightning arrestor in an antenna system.

 

[sdkubota]

Maske sure you have #6 cable to supply the 50 Amps...stuff is like battery cables.

 

[CNC Dan]

Hm. I guess I was thinking of it being like a lightning arrestor in an antenna system.

that would be more like a filter. And those have their place too.

inside surpressors are like two diodes in series, oposeing. They won't conduct untill the reverse breakdown voltage is reached, then it acts like a short. unlike the diode pair, once the higher voltage is gone the supressor stops conducting.

 

[Willl]

Maske sure you have #6 cable to supply the 50 Amps...stuff is like battery cables.

#6 ???