ThrownRazor25

Hiya guys will an RCD or RCBO work if there is no earth in the house?A fellow worker said to me today that there is no need for an earth in a house if the board has an RCD or is controlled by RCBOs as they work on the inbalance of the live and neutral.

PAUL M

Tell Your Mate He Is Talking Out His Ass,of Course You Have To Have An Earth,they Work By Detecting Earth Leakage.

ThrownRazor25

Thats what i said to him bud but he was adamant cause he had done his 17th and ive no i started questioning myself.

danzor

I would question his 17th qual

Cirrus

Or any quals!!!

wayne

the guy has the half baked opinion that sends us to the text boooks to check

LukeScotty

correct me if i am wrong here, but its not that they detect the earth leakage persay, but of an imbalance of the neutral and line, due to current flowing via earth... ?

Luke

If You Build It, They Will Come!!!!!

MacSparky

why do you need a seperate earth to make rcd,s and rcbo's work? an rcd will actuate at around 22-30 milliamps, either of the phase conductors could come loose and touch exposed metal work which would allow the cpd to work,(connected to cpc or not),..... surely as scotty mentioned its a minute inbalance that would trip them....earth leakage that is. Non rcd/rcbo cpd's would require cpc for sure. Hope i'm not missing the point here

Get off my planet...
http://www.mysportydate.com/

Shakey

everyone is a bit right - and some are a bit wrong here.

An RCD does not need an Earth per se, but needs an EARTH PATH

it is quite conceivable to have a house with no incoming earth, but there would be an alternaive path though the CPC to the MET, through the protective bonding and down to earth though any extraneous conductive paths (gas, water pipes etc)

as long as that path is 1667 ohms or less, the RCD would trip before the fault voltage reached the magical 50V, and even with a path of 7666 ohms or less would still trip.

Of course we need an earth path for CPD's to work correctly, but an RCD, with ANY path to earth as stated above, will trip off

and before anyone starts thumping the keyboard, I am NOT suggesting using an RCD means you dont have to have an incoming earth

PAUL M

yes i know that but if there no earth path what then.