uHeat Banner - Forum Discount Available
This official sponsor may provide discounts for members

Discuss Help!!!!!!!!!!!!!!!!!!!!!!! in the Electrical Wiring, Theories and Regulations area at ElectriciansForums.net

Welcome to ElectriciansForums.net - The American Electrical Advice Forum
Head straight to the main forums to chat by click here:  American Electrical Advice Forum

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.
 
P

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.
 
  • Thread Starter Thread Starter
  • #3
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

-
Mentor
Arms
I would question his 17th qual
 
W

wayne

the guy has the half baked opinion that sends us to the text boooks to check
 
Tell Your Mate He Is Talking Out His Ass,of Course You Have To Have An Earth,they Work By Detecting Earth Leakage.
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
 
M

MacSparky

why do you need a seperate earth to make rcd,s and rcbo's work?:confused: 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:)
 
Last edited by a moderator:
S

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:p
 
P

PAUL M

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

jeremy

-
Mentor
Arms
Tr25 you say he has done his 17th, 17TH what ??Joint before Breakfast!! (and I'm not talking crimped)Anything without an earth return becomes a special location that is not allowed under normal circumstances, ie domestic installations
 
  • Thread Starter Thread Starter
  • #12
Listen mate im on your side lol.Hes a wee know it all ---- who has done a 17th course and is spouting out all this crap all the time.trouble is he is so sincere about it half the guys at work are starting to believe him.He is adamant the new regs say that if the board is protected by an rcd or if individual circuits all have rcbos then there is no need for an earth because the rcd/rcbo will operate on the imbalance of live and neutral.
 
S

Shakey

Listen mate im on your side lol.Hes a wee know it all ---- who has done a 17th course and is spouting out all this crap all the time.trouble is he is so sincere about it half the guys at work are starting to believe him.He is adamant the new regs say that if the board is protected by an rcd or if individual circuits all have rcbos then there is no need for an earth because the rcd/rcbo will operate on the imbalance of live and neutral.
ok, I have explained how an RCD COULD work without an incoming earth with an extraneous path of 7666 ohms or less (but probably not in the required time), but that is an accidental by-product of there being no earth in the first place

How the hell does this guy think ADS will be achieved:eek:

I teach 17th edition, and this guy is talking utter tosh

he has no doubt misenterpreted something he was told on the course

along the lines of RCD protected circuits only needing a Zs of 1667 ohms or less for their 60898 MCB's etc etc

If you want to 'douse his flames' a little, ask him for the relevant regs numbers to back up his 'theories';):p
 
M

Moog

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
I agree it will trip if the phase and neutral currents are not the same, however I would not sign off an installation without an adequate earth path unless it was SELV for instance You sure this guy isn't on about bonding? not done my 17th conversion yet but there was take about there not being a requirement for bonding in bathrooms anymore
 
Last edited by a moderator:
S

Shakey

I agree it will trip if the phase and neutral currents are not the same, however I would not sign off an installation without an adequate earth path unless it was SELV for instance You sure this guy isn't on about bonding? not done my 17th conversion yet but there was take about there not being a requirement for bonding in bathrooms anymore
bit more complicated than that Moog, for bathrooms, but yeah, if all conditions are met, then no supplementary
 
CK Tools :) The professionals choice when it comes to Electrical Tools
This official sponsor may provide discounts for members

Reply to Help!!!!!!!!!!!!!!!!!!!!!!! in the Electrical Wiring, Theories and Regulations area at ElectriciansForums.net

Top Bottom