AC switch fault current philosophy

I'd say that the short-circuit behaviour of the mains is one of the most important parameters of the wiring. In Poland exactly this parameter (the short-circuit loop resistance) must be measured every

5 years by a qualified technician in order to allow the further operation of the flat/house installation. The wiring just can't be barely enough, something in the order of 5-10x current capacity for a short period must be ensured in order to make the fuses blow. My worst-case is 0.5Ohm, with 0.38Ohm being the most frequent value.

Best regards, Piotr

rote:

the

end

c or thermal?

ur 'safety

rotection.

bilities of a hypothetical breaker at an unknown upstream point, not so muc h.

I presume they are in all other 1st world countries too.

In the UK it sometimes does

you guys seem determined to not get it. Protection can be split between 2 d evices, as long as in all scenarios safe protection occurs. That CAN be don e, and safely, by using the breaker to trip in some situations. Splitting t he protection happens day in day out over here.

t if for any reason the supply fails to. That could be as simple as a fusib le resistor.

I guess you're in America. I'm not.

NT

----------------------------

** I like to use a 10 amp load like a fan heater of electric kettle while monitoring the voltage with a DMM.

Monitoring the wall outlet itself ( A-N )results in about 5 to 10 volts drop, so the supply impedance is 0.5 to 1 ohm. You could also monitor from N-E and double the reading.

From this you can infer the short circuit current will be between 240 and 480 amps - so will INSTANTLY trip a 16A fuse or magnetic breaker.

.... Phil

So you think an appliance must have a fuse must be fitted to make it safe?

Don't be silly. Dishwashers, electric stoves, clothes washer/dryers, refrigerators et al have grounded metal cabinets. No fuse is required for electrical safety for people using them. Double insulated tools prevent people from contacting an electrical fault.

Ed

----------------

** FFS - that is what **YOU** just claimed. I say your original premise is FALSE. ** MASSIVE RED HERRING ALERT !!!!!!!!!!!!!!!!!!!!!

That was never the question - you desperate, damn LIAR.

Fuses and breakers provide NO protection against electric shock.

They provide minimal, fire hazard protection and little more.

FYI d*****ad:

Earthing of metal cases provides shock protection ONLY if the metal really IS earthed. Lotsa ways it can wind up live instead.

User replaceable fuses cannot be relied on to provide protection of any kind.

Installed breakers provide fire protection for installed cables and appliance cables in the vast majority of situations too - but no fire protection for appliances themselves.

Go away you damn fool.

.... Phil

8<

He's just trolling.

but that section contains errors. I don't expect any reasonable response from you, hence it's not even worth getting into it.

Phil, You either suffer from a serious reading deficiency, or you're a liar.

Goodbye.

Ed

Is it possible to separate the current limit functionality from the mains breaker trip? Limit the current first and always, sense an over current state, and then leisurely use a low voltage to trip the mains breaker a few cycles later?

Thank you,

--
Don Kuenz, KB7RPU

I mean, a shunt breaker does that, but you mean a regular mains breaker? How would you connect the "low voltage"?

Tim

--
Seven Transistor Labs, LLC 
Electrical Engineering Consultation and Contract Design 
Website: https://www.seventransistorlabs.com/

RS-232's the old school way and it's probably the most reliable. WiFi's probably cheaper.

Remote Setup, Control, and Monitoring in One Panel

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(excerpt)

Thank you,

--
Don Kuenz, KB7RPU

Ah, sure -- that'll do, just remember operation might not be guaranteed (Wifi anyone? :) ), so the self contained breaker action is still needed. A keep-alive loop might be acceptable to rely on, whether in very basic hardware like a 4-20mA loop, or in software like a serial watchdog.

It'd be a natural for integration into a panel like that. Though as fuses and breakers have done just fine over the last century, it seems unlikely you could justify the cost, except in extraordinary situations (like aerospace SSPCs).

Tim

--
Seven Transistor Labs, LLC 
Electrical Engineering Consultation and Contract Design 
Website: https://www.seventransistorlabs.com/

One of my clients uses such a system in his home. When he's away from home he VPN connects to his home panel and uses a web browser to keep an eye on things. He can control any light in the house (and probably outlets too.) Granted, it's a more expensive. But it's also relatively common, if the quantity of companies that service such home panels is any indication. It looks like Eaton offers a guy that retro-fits into an existing panel.

Remote Controlled Circuit Breakers

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Thank you,

--
Don Kuenz, KB7RPU