Page 2 of 5 FirstFirst 1234 ... LastLast
Results 11 to 20 of 49

Thread: Does a stove need to be on an earth leakage?

  1. #11
    Full Member
    Join Date
    Jul 2015
    Location
    Jouburg
    Posts
    30
    Thanks
    0
    Thanked 3 Times in 3 Posts
    Having just tried to memorise SANS 10142, I can confirm

    6.7.5.5 The following do not need earth leakage protection:

    ..

    d) a stove coupler that complies with SANS 60309-1/IEC 60309-1 and of
    dimensions as given in SANS 337 (see 6.15.1.2.5). Amdt 5


    What exactly this makes in terms of nullifying the need for protection I cant say.

  2. #12
    Bronze Member
    Join Date
    Oct 2014
    Location
    Pretoria
    Posts
    126
    Thanks
    16
    Thanked 16 Times in 15 Posts
    So in saying all this in this discussion about removing stoves and lights from earth leakage protection, who of you actually do the earth resistance test and continuity of bonding before doing this?
    Just remember that the earth leakage is not the primary form of protection, its an added protection.

  3. #13
    Bronze Member Didditmiself's Avatar
    Join Date
    Sep 2012
    Location
    South Africa
    Posts
    180
    Thanks
    31
    Thanked 26 Times in 18 Posts
    Precisely! The only reason anybody would decide to remove an earth leakage CB is because of it being a nuisance. If it trips, then better to look for the fault.

  4. #14
    Bronze Member
    Join Date
    Oct 2014
    Location
    Pretoria
    Posts
    126
    Thanks
    16
    Thanked 16 Times in 15 Posts
    Quote Originally Posted by Didditmiself View Post
    Precisely! The only reason anybody would decide to remove an earth leakage CB is because of it being a nuisance. If it trips, then better to look for the fault.
    Or in the case of an new installation one would design the installation as such to only have socket outlets under earth leakage protection (also other devices which could require E/L protection), also only after satisfying oneself that the earth resistance of the earth continuity conductor is within the required earth resistance limit in accordance to the protective device. Therefor also avoiding nuisance tripping of the earth leakage, but still offering the primary form of protection on all electrical devices and continuity of all conductive surfaces which could become live in the case of malfunction of electrical devices or wiring.

    I prefer to have everything under E/L, but that is my preference and not the industry requirement and with saying that it will not just be one earth leakage. I would install a separate earth leakage for my plugs and at each sub board it's own (swimming pool/garage/ etc.) I cannot enforce my own preferences onto my client, it is a "nice to have" and extra form of protection which is not required. With larger developments this would for sure make the cost difference an enormous amount. Normally one can see especially with larger developments who the the inexperienced electricians are due to the fact that everything is wired underneath earth leakage, because having everything under E/L means then the sparky can get aways with doing a poor job...

  5. #15
    New Member
    Join Date
    Aug 2015
    Location
    Springs
    Posts
    2
    Thanks
    0
    Thanked 0 Times in 0 Posts
    Forget what SANS says for a minute, and let's break this down... The stove trips the earth leakage; electrician removes the stove circuit from the earth leakage; earth leakage doesn't trip any more; problem solved, right? Can any proper qualified electrician honestly tell me that he'll go home and NOT worry WHY the stove caused the E/L to trip in the 1st place, plus now he's just removed an essential SAFETY device from the stove circuit?

  6. #16
    Full Member
    Join Date
    Jul 2015
    Location
    Jouburg
    Posts
    30
    Thanks
    0
    Thanked 3 Times in 3 Posts
    As long at the external conductive surfaces are earthed on a stove, isn't that the major safety base covered? just asking ...

    Also still wondering why you don't have a stove on EL if that specific plug/socket is used as per the regs? Why would that change anything to do with safety as far as EL / Residual Current is concerned?

    Can't see any point in putting lights on EL, but if it makes one or the client feel safer, then why not, but using multiple units per sub circuit might make this less trouble.

  7. #17
    Diamond Member AndyD's Avatar
    Join Date
    Jan 2010
    Location
    Cape Town
    Posts
    4,363
    Thanks
    509
    Thanked 849 Times in 682 Posts
    Quote Originally Posted by kosmonooit View Post
    As long at the external conductive surfaces are earthed on a stove, isn't that the major safety base covered? just asking ...
    People getting electric shocks is an extremely serious matter because a few milliamps traveling though some poor soul can cause their death. Electrical installations have a belt and braces approach to stopping people getting shocked. For someone to get shocked under normal circumstances requires that there's two serious faults happening simultaneously and either of these faults must, according to the regs, be repaired immediately upon being discovered.

    Firstly we have the earth wiring which should prevent the chassis of any item or appliance from becoming at a voltage that can give someone a shock (touch voltage). There's a few problems with this, corrosion, poor connections and terminations, trailing cable damage and even missing connections often make the earthing inadequate or even ineffective. Add to this the fact that when it's tested by an electrician the tester being used actually passes a few miliamps through it during the test; even the best tester will only use a few Amps whereas under fault condition the earth wiring may need to carry hundreds or even thousands of Amps momentarily and invariably that's when any weaknesses show themselves. As soon as a single earth is missing or inadequate, the surrounding equipotential zone that was providing user safety then becomes your worst enemy.

    Under normal conditions a missing or inadequate earth won't cause injury, it does however mean that if there's another fault on the same circuit it can be lethal.

    Secondly we have insulation. This is the medium that separates the current carrying parts of the circuit from the other parts of the installation that can be touched by a user. It ensures that current stays withing the circuit and doesn't 'leak' out and find it's way to earth through unauthorized paths. Failure of the insulation and the potentially dangerous condition it can cause would be detected firstly by the earth leakage breaker which would usually trip when around 25(ish) miliamps is leaking. If there's a complete failure of the insulation then a much larger current will flow which will cause the normal circuit breaker that's supplying that particular circuit to trip. This only protects the circuit wiring from overload, it won't protect someone who gets a massive shock, they'll be long dead by the time a 10 or 20A circuit breaker has disconnected by tripping. Insulation faults are also deemed by the regs to require immediate remedy.

    As with the earth fault, an insulation fault on its own won't cause injury or give a shock because the earth is preventing the faulty item developing a 'touch voltage'.

    So no single fault will cause a shock but ignoring an insulation fault puts all the eggs in one basket leaving the earth as the only protection. Not acceptable. A circuit tripping an earth leakage breaker and being removed from the earth leakage protection...not acceptable.

    Don't treat the symptoms, treat the actual cause. Find the damn fault and fix it.



    Quote Originally Posted by kosmonooit View Post
    Also still wondering why you don't have a stove on EL if that specific plug/socket is used as per the regs? Why would that change anything to do with safety as far as EL / Residual Current is concerned?

    Can't see any point in putting lights on EL, but if it makes one or the client feel safer, then why not, but using multiple units per sub circuit might make this less trouble.
    I'd suggest nowadays we should actually be using domestic DB's with dual e/leakage protection as a minimum with one E/L for the sockets and one for the remainder of the installation. There's no reason not to, the cost has reduced to such a point where it's no longer an issue and using two E/L breakers gives a safer installation without the annoyance of the entire power going off every time there's tripping. We should in fact be using RCBO's giving earth leakage protection on every single circuit individually but whilst they've been the norm overseas link1 link2 link3 link4 for the last few years they don't even sell them in any of the major SA wholesalers yet .
    _______________________________________________
    I am special and so is Vanash.
    _______________________________________________

  8. #18
    Bronze Member Didditmiself's Avatar
    Join Date
    Sep 2012
    Location
    South Africa
    Posts
    180
    Thanks
    31
    Thanked 26 Times in 18 Posts
    Andy, what are RCBO's? Maybe someone else mentioned it but I missed it.

  9. #19
    Diamond Member AndyD's Avatar
    Join Date
    Jan 2010
    Location
    Cape Town
    Posts
    4,363
    Thanks
    509
    Thanked 849 Times in 682 Posts
    An RCBO is similar to a normal circuit breaker but it also provides 30mA earth leakage protection as well as the standard overload protection on a circuit by circuit basis.

    The average domestic installation has a single earth leakage breaker that protects the entire installation which introduces a few problems. For example a single earth leakage fault on only one of the circuits causes the entire installation to trip in most cases which certainly isn't ideal. Also many electronic appliances have an acceptable amount of background earth leakage during their normal operation. This background leakage can accumulate to a substantial amount if there's several PC's, TV's and fluorescent lights or LED drivers being supplied and it can cause annoyance tripping of the earth leakage breaker even though there's not actually a fault present.

    Using RCBO's means that every individual circuit has it's own 30mA earth leakage protection so if there's an earth leakage fault on any one circuit, only that circuit trips.

    This is a single pole RCBO, it only interrupts the live of the circuit, the neutral connection you can see is just for reference.

    Click image for larger version. 

Name:	Schneider RCBO.gif 
Views:	79 
Size:	21.6 KB 
ID:	5842

    The problem with just interrupting the neutral with an earth leakage fault is that whilst the circuit will become dead the fault won't actually be cleared if it's N-E leakage. That's why it's better to use the type below which is 2-pole, it disconnects the live and the neutral together if there's a fault. (It's actually an SP+N type circuit breaker because it only provides overload protection monitoring on the live wire, not the neutral.)

    Click image for larger version. 

Name:	GE RCBO.jpg 
Views:	75 
Size:	35.6 KB 
ID:	5843
    _______________________________________________
    I am special and so is Vanash.
    _______________________________________________

  10. Thank given for this post:

    CLIVE-TRIANGLE (27-Aug-15), Didditmiself (26-Aug-15)

  11. #20
    Diamond Member Justloadit's Avatar
    Join Date
    Nov 2010
    Location
    Johannesburg
    Posts
    2,662
    Thanks
    87
    Thanked 543 Times in 459 Posts
    Blog Entries
    1
    I arrived recently from an overseas trip, and took note of the DB in the apartment I used. Interestingly, in this 2 bedroom apartment, two toilet, and lounge, there was 8 RCBO's separating lights in rooms, plugs in rooms, appliances. Each circuit breaker was numbered, and a table on the door indicated exactly what each circuit breaker was protecting. Any laymen by identifying the tripped breaker number would immediately be able to identify the fault location.

    On second thought, I should have taken a picture when I looked.

    I thionk we got a long way to go to follow this route. In my mind this is the way it should be done.
    Victor - Knowledge is a blessing or a curse, your current circumstances make you decide!
    Solar and LED lighting solutions - www.microsolve.co.za

Page 2 of 5 FirstFirst 1234 ... LastLast

Similar Threads

  1. Earth leakage trips at night??
    By Jongseun in forum Electrical Contracting Industry Forum
    Replies: 18
    Last Post: 18-Jun-12, 10:47 PM
  2. earth leakage unit failure
    By murdock in forum Electrical Contracting Industry Forum
    Replies: 11
    Last Post: 23-Feb-12, 08:37 PM
  3. Random earth leakage problem
    By BillH in forum Electrical Contracting Industry Forum
    Replies: 39
    Last Post: 23-Jan-12, 09:37 PM
  4. stove plate
    By murdock in forum Technology Forum
    Replies: 7
    Last Post: 31-Mar-10, 11:24 PM
  5. CBI earth leakage units
    By murdock in forum Electrical Contracting Industry Forum
    Replies: 2
    Last Post: 29-Oct-09, 12:44 PM

Did you like this article? Share it with your favourite social network.

Did you like this article? Share it with your favourite social network.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •