Need fuse for volts

[peter]

I figured that would get your attention because I used to write famous headlines. ["McGovern Sweeps Massachusetts"]

Anyway this is the problem: I plugged my Makita battery charger into a supposed 115 volt source attached to a spider box and it immediately blew up. Well it made a pop and released maybe an ounce of white smoke. I investigated with my volt meter and got readings like 179 volts and more. It turns out at it was plugged into a 240 volt outlet on the main spider box and was jury rigged with the white neutral attached to the ground prong. And the ground wasn't very good.

Mow I know that we have fuses and circuit breakers which protect against over amperages. Surge strips and the like seem designed for transient over voltages. What I would like is some simple device which would cut off instantaneously at say 140 volts or over.

Any Teslas out there?

~Peter

 

[tonyi]

Re: Need fuse for volts

Not exactly "simple", but some UPS's will go to battery on sustained over voltages.

In the scenario you described though, it would probably waste the UPS

[ February 02, 2004, 02:23 AM: Message edited by: tonyi ]

 

[hurk27]

Re: Need fuse for volts

This would be easy just place a couple GE MOV's down stream from a fuse if the voltage is over the MOV threshold it will blow the fuse.
If you have a plug strip with a breaker just put the MOV's after the breaker. a couple 130 volt MOV's paralleled will trip a 15 amp breaker with no problem. I use them in all my high end electronic's just after the main fuse so if I ever get an over voltage to them the fuse will blow.

[ February 02, 2004, 06:59 AM: Message edited by: hurk27 ]

 

[peter]

Re: Need fuse for volts

Thanks for the replies.
Do you mean I can take a power strip and open it up and install the MOVs? How exactly would they be connected?
~Peter

 

[hurk27]

Re: Need fuse for volts

I shouldn't have said that, as that would remove the UL listing. but if you were to use a external single plug in surge suppressor maybe two of them and plug them in to the strip. and this plug strip has a breaker on it some are 10 amp and some are 15 amp but I know that at least two surge suppressors would trip the breaker on the strip thus protecting anything that was pluged into it. I have had surge suppressors trip my 200 amp main durring a over voltage fault from the POCO about a year ago.

 

[dereckbc]

Re: Need fuse for volts

How about buying a raceptacle with built-in UL 1449 TVSS rating?

[ February 02, 2004, 10:49 PM: Message edited by: dereckbc ]

 

[dereckbc]

Re: Need fuse for volts

How about installing a receptacle with built-in UL 1449 TVSS rating?

 

[tom baker]

Re: Need fuse for volts

An MOV is a metal oxide varisitor. Typically it is open circuit at 130 volts and then clamps really really fast at 140 volts +. This little red 0.39 cent item is what is in most of the 3.99 TVSS strips you see that are not UL 1449 listed.
I used to wire the TVSS in on the line side of electronic equipment, but in a overvoltage, it would fail shorted, trip the breaker and be a callout. Now I use a wired in TVSS with remote alarm contacts.
Derecks idea should work fine as long as the fault current is low enough. If the fault current is high enough it will vaporize the MOV.

 

[tom baker]

Re: Need fuse for volts

An MOV is a metal oxide varisitor. Typically it is open circuit at 130 volts and then clamps really really fast at 140 volts +. This little red 0.39 cent item is what is in most of the 3.99 TVSS strips you see that are not UL 1449 listed.
I used to wire the TVSS in on the line side of electronic equipment, but in a overvoltage, it would fail shorted, trip the breaker and be a callout. Now I use a wired in TVSS with remote alarm contacts.
Derecks idea should work fine as long as the fault current is low enough. If the fault current is high enough it will vaporize the MOV.

By the way GFCI's have small TVSS's inside. This TVSS can fail after repeated overvoltages...

 

[hurk27]

Re: Need fuse for volts

Tom what I use them for and still do is I place a fuse ahead of the MOV and if a loose neutral or like what happen here last spring a long duration surge it will blow the fuse. In most strip's I have looked at the MOV's are ahead of the breaker and will not trip the built in breaker this allows the MOV to burn open (after they go short) and I have even seen two that burned the carpet the strip was laying on. which could be a fire hazard. buy using a regular non-surge protector type strip and then plugging a surge suppressor into this strip it will trip the breaker on the non-surge protector type strip. What I was suggesting earlier was placing the MOV's after the breaker or fuse to allow it to open in the event of any type of over voltage surge. This would protect anything that is also on the load side of this fuse. For over twenty years I have been doing this to all my electronics. I would connect it to the power right after the main power fuse.All my power amps and TV's have one in it. I even have one high end stereo that has a factory MOV in it but they (the manufacture) placed it before the fuse and it does no good for long duration surge like when a neutral is lost. I have seen many microwaves that are setup like this also and the MOV just Frie's. without blowing the fuse. I was told one time that the reason the manufactures do this is if the MOV is cooked they know that the unit was subject to high voltages = No warranty
So I have just taken my own way to protect my equipment.

 

[peter]

Re: Need fuse for volts

Hurk,
So I get two power strips -- one with surge suppression and one without. I plug the one without into the questionable source and then plug the power strip with the surge suppressor into the first one and then plug my little blue battery charger into that.
Thank you Nick,
~Peter

 

[pierre]

Re: Need fuse for volts

Would it not be easier and safer to use a voltage tester and forget about jurying rigging some halfa$$ solution.

Pierre

 

[hurk27]

Re: Need fuse for volts

It probably would, but how long would you sit there and watch it. loss neutrals come in the middle of the nite LOL

 

[peter]

Re: Need fuse for volts

Pierre, [nice name by the way]
How many times do you whip out a VOM and test the voltage on a 110v receptacle before you plug in your electric razor?
~Peter

 

[pierre]

Re: Need fuse for volts

Peter
I was almost named Peter, but my parents saw fit to make sure that I would get use to insults at an early age

I know that hurk has the proper skills and knowledge, but my concern is that others would read his posts and try it for themselves.
When I shave, I still use a blade

Pierre