Earth Fault

Safety, insurance, code compliance......Death, liability, criminal charges, jail....

Earth fault protection (known also as ground fault protection) is there to prevent a lethal current flow in the event of a short from supply (hot wire) to ground (typically through the victim).

It is there to save lives. The only reason not to include it: considerable overpopulation, and a cavalier attitude about the best way to "Darwinize" the less cautious of the group.

I wonder why you are the first CR4 member to use "Cavalier" and "Darwin" in the same sentence?

'Tis only a miracle that I am here to report the dangers of a Cavalier attitude. I have had several close scrapes with becoming a Darwin award recipient. I suppose that could be why? It always give me halt when someone asks why I should mention those two words in the same sentence.

Could it also be that automotive engineering has evolved far past the Cavalier, hence the reference to Darwin?

Hey when I first saw this thread I was not sure we were not talking about the 7.8 magnitude earthquake in New Zealand over the weekend.

When I rode motorcycles, I thought was about to become a statistic more than once.

Some of those occasions were alcohol induced flirtations with the Darwin theory.

Because they perform two separate and distinct purposes. Overcurrent protection is there to protect the wiring, not the equipment and certainly not a human. Earth fault protection is there to protect against high impedance faults such as arcing faults, gradual insulation failures, and as others have said, human/animal contact.

The risk is that the courts will hold you and your company liable for any lawsuits/damages for not designing the system to meet all applicable codes for the installation's locale.

Earth Fault device trips if it sees any current. Over current trips when it excedes the rate current of the device. So if your being electricuted and you depending on a 20 amp breaker to trip may never happen. All depends on the resistance to ground.

Risk is having your love one come home and finding you still smoldering because the breaker never tripped. Or the other way around.

It doesn't take much current to kill you (0.2A will do it).... vastly less than the current rating of any fuses or other over current protection.
Del

Is it me or are the questions these days getting dumber?
If the OP has to ask, then he should stay playing with his Lego set, get off the internet and take up something useful, like trash collection in his spare time!

Ye Gods Fadhel.. its ideas like yours that KILL people!

Be honest, are you a student, a practicing trainee engineer or just plain dumb as you didn't learn anything in college and expect CR4 to educate you?

It's not you.

thanks for those reassuring words Lyn.. I was beginning to think I was going over the edge!

GA

Don't you know the defferences between an overcurreent and a earth faults protection....

I think you'll find the answer to your question in the post itself!
Better idea.. let me answer for the OP...
Mmmmm, let me think, let me think, let me think....

NO!

Rubbish!

I work with people for who English is their third language and they have MADE the effort understand and comprehend the spoken and written word.
So are you saying this guy does not comprehend?

I surely forgot the word "sometimes", my bad. No, not in general.

I'm almost positive this gut person was Legolez or some such other name and something else before that.

He has been banned twice before for being a troll, as you can see.

Go stick your head in the toilet and flush that little berry of a brain, or go read a dictionary.

Simple:

• Overcurrent protects the wires
• Earth Fault takes care of the rest (humans and property)

Only 18mA is required to kill you, if passing through the hart.

The different types applied are due different tasks and visions of the regulatory bodies.

In the US domestic installations you will mainly find 4mA types build in the outlet. These are of the slow type so they don't react on a bouncing switch or the inrush effect of an appliance. As they are typically build in the outlet the wiring upstream is not protected.

In Europe you will find two in each house:

• 300mA main at the entry of the house (as of this point the owner is legally the sole responsible of the installation, upstream it is a bit complex and depends) This protects the house for any fault in the wiring resulting in leakage to the earth.
• 30mA for all zones were water is influencing the safety aspect of electricity. Protecting the humans.

These are of the fast reaction type: any occurence of a residual current surpassing the trip level should trip the device. A device is allowed to trip as of 50% of that current.

An earth fault protection does not catch all faults that might result in arcing, nor does every short circuit be detected by the overcurrent protection. If your wire is too long the current will not be sufficiently long high enough to trip the fuse.

Arcing is very difficult to detect with simple reliable techniques. (no software is to be used in safety/protective devices if possible) In very specific situations where it is expected to have arcing occur and the value/risk is important, it gets installed additionally to the protection of the device. Such a device typically costs more than a normal house electrical installation.

Rules and regulations are in the first place there to protect you and your property, of course the money involved at insurance and equipment supplier level is the main driver for rules to become imposed. In this case you simply profit from it as the insurance fees can go down and loss of property and life is limited.

Not Darwin.

Not Darwinize. (Convert to Darwin, cloning perhaps)

DARWINIVATE. (The process of applying Darwinian principles to a candidate)

The word <...we...> in this post is undefined.

Why on earth wouldn't one?

Because 'we' wouldn't!