Never Trust The Test Switch On An Rcd

[Gardner]

This is why. Looks all good until you find out live is still very much live:

At least the other one works:

 

[Midwest]

That's Americans for you.

 

[Pete999]

Maybe a SP GFCI and the receptacle has reversed polarity

 

[Bobster]

Also, a GFCI and an RCD don't work the same way.

 

[Pete999]

Didn't know that,what is the difference? interested honestly

 

[Gardner]

Didn't know that,what is the difference? interested honestly

An RCD is usually 30ma in the UK while a GFCI is 5ma in the US. A GFCI in the US is intended to provide protection against electrocution. Internally they have electronics while UK RCDs to my knowledge are electromechanical.

 

[Gardner]

Maybe a SP GFCI and the receptacle has reversed polarity

No double pole and wired correctly. Most likely one of the contacts (the live) welded shut.

 

[bigspark17]

Jesus he loves pressing that test button!!!

 

[Midwest]

Jesus he loves pressing that test button!!!

My brother-in-law like that, the switch is off, now it's on, now it's off, now it's on, on off, on off.........Jesus turn the f'ing light off!

 

[Bobster]

Didn't know that,what is the difference? interested honestly

GFCI's or the ones I have worked with use electronics to detect the current imbalance, and are usually for sockets rated at 5mA

RCD's here, as you know use a toroidal transformer to detect the imbalance.

 

[Gardner]

Jesus he loves pressing that test button!!!

LOL! I know. But to anyone posting in US forums you would understand. I was trying to prove a point that the GFCI had indeed tripped and was resting correctly. These units are such that if they fail they will either not trip or not reset after they trip alerting you the GFCI is malfunctioned. In the US there is this misconception that the test/reset button will tell you all you need to know about a GFCI.

 

[Bobster]

I think the real joke, or certainly in the states I've worked in is the shear lack of understanding behind testing.

Even electrical theory in general, I'd say the majority of even what are classed as 'master electricians' don't understand what they are installing and how it works, only that the NEC tells them it must be done that way.

 

[Gardner]

I think the real joke, or certainly in the states I've worked in is the shear lack of understanding behind testing.


Even electrical theory in general, I'd say the majority of even what are classed as 'master electricians' don't understand what they are installing and how it works, only that the NEC tells them it must be done that way.

Its the status quo to be honest. And the truth is both the NFPA and UL are egging it on. The NEC has very few testing requirements and UL says the test buttons are sufficient for verifying GFCIs. Bring that up in a US forum and you get chewed up. But come reality we have black and white proof why such a mentality is actually masking a life safety hazard. Remember, we may use 120 volts but there is still a danger: a HUGE number of 2 prong appliances in US kitchens require a GFCI to prevent them from becoming an electrocution hazard. Considering threads like this it leads me to believe this not an isolated problem:

https://www.nachi.org/forum/f19/g-f-tripped-and-still-has-power-81497/


Its ironic because when GFCIs first came out (to cover for the fact nearly every two prong metal framed tool did not have an earth pin and people were dropping like flies) they had very high failure rates both mechanical and electronic. Manufactures started adding MOVs and various improvements were rolled out. It still was not enough so latter on manufactures added self diagnostic lights, Levlock technology (which this GFCI had) which basically prevents a GFCI from being reset if it has an internal failure and as of recently UL requires all GFCI be self testing. If the GFCI does not pass its internal self test it must trip and become inoperative, a feature which raises the cost of new GFCIs substantially.

http://www.leviton.com/OA_HTML/SectionDisplay.jsp?section=66915&minisite=10251

But regardless of all the $$$$ and feel goods not one of these gimmicks stops or will stop the above from happening. GFCIs will continue silently fail without any indication.

 

[Bobster]

Oh I know all to well about UL, the panels we build here have to meet the standard (obviously). Never done domestic work in the US, I'm involved with factory automation.

We get inspected quarterly to make sure we are certifying correctly etc... the amount of arguments I've had regarding pretty basic physics is mind blowing, very much a case of, it's what it says in the paper please blindly follow it.

 

[Gardner]

Yup. The US is mindless submission from the top down. It comes from the public schools which are nothing more than legalized child abuse. Trauma based mind control to get the entire population to follow rules and laws which have absolutely no bases in reality. I know because I've seen it first hand. Trust me, I did not have it easy nor did I make many friends.

 

[Gardner]

Guess I am not the only one:

 

[Sisyphus]

The real problem, imho, is lumping electronics onto a torodial coil. While most electricians can discern ohms & kichoffs laws ,we are not trained in the intricacies of electronica , cpu's, etc.

Conversely , methinks it could be universally agreed any given sensitive electronica installed across mains of nefarious swells, sags & spikes may have less a life span and/or assume woes the ave spark is unable to pinpoint.

The notion of exactly just what the test button tests becomes something of a mystery ,if not a frustration here.

UL ,in their ever lofty goal to save us from ourselves, has moved from a lock out feature , onto a self test feature

Go Here if you're so inspired , but don't expect specifics.

~S~

 

[Gardner]

The real problem, imho, is lumping electronics onto a torodial coil. While most electricians can discern ohms & kichoffs laws ,we are not trained in the intricacies of electronica , cpu's, etc.

Conversely , methinks it could be universally agreed any given sensitive electronica installed across mains of nefarious swells, sags & spikes may have less a life span and/or assume woes the ave spark is unable to pinpoint.

The notion of exactly just what the test button tests becomes something of a mystery ,if not a frustration here.

UL ,in their ever lofty goal to save us from ourselves, has moved from a lock out feature , onto a self test feature

Go Here if you're so inspired , but don't expect specifics.

~S~

Electronics are always a bad idea, one transient and they are gone. Few in North America think about it.

 

[GLENNSPARK]

The 'test Button'...is there to keep the mechanism free and working

Hard neutral-earth faults can 'freeze' an RCD...

 

[Sisyphus]

I agree Glenn. In fact there's also a UL standard that all OCPD's be mechanically excersized to address just that.

That said , as Gardner suggests, electronic integrity may be easily compromised, so what actual diagnostics beyond mechanical becomes a curiosity , if field accessible for assessment at even basic levels

Fwiw our afci's are also suspect , given they incorporate electronica the size of a pea able to discern waveform anomalies gifted EE's armed with oscilliscopes the size of a Buick may have trouble with.

~S~