Which regulations cover the safety of an alternate supply connected to switchboard?




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    Default Which regulations cover the safety of an alternate supply connected to switchboard?

    I always advocate that licensed electricians connect inverters to a home's switchboard. But mostly the electricians turn around to me and ask me how to do it. Where do I send them to go and do their homework? No two electricians have yet done the same thing - some use earth leakage on the alternative feed, some have pilot lights at the board, some have 4 pole isolators to cut both alternate and Eskom, etc.

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    Default Re: Which regulations cover the safety of an alternate supply connected to switchboar

    Quote Originally Posted by Jonatan View Post
    I always advocate that licensed electricians connect inverters to a home's switchboard. But mostly the electricians turn around to me and ask me how to do it. Where do I send them to go and do their homework? No two electricians have yet done the same thing - some use earth leakage on the alternative feed, some have pilot lights at the board, some have 4 pole isolators to cut both alternate and Eskom, etc.
    You not alone with this problem. To get my invertor connected took 3 "qualified" electricians. The 2 locals just couldn't figure out the EL issue.

    The last 1 from Zimbabwe who was far more professional and genuinely qualified, bonus was he actually had his own equipment. Took less than an hour to sort out all the shyte from the previous 2 local electricians. He even had spare EL in his tool box to replace my faulty 1.

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    Default Re: Which regulations cover the safety of an alternate supply connected to switchboar

    I'm in the same boat. I've had 2 electricians in - one said they could separate the inverter switches on the board and mark clearly, the other said that they would have to install a second DB for the inverter. I'm keen to go with the neater and cheaper option of just creating 2 groups of switches in my existing DB, but I'm not sure if this is legal. My inverter power currently runs to the DB via a big changeover switch, so I have to turn off most of the plugs, geysers, etc. then switch over each time there is loadshedding. But the inverter does have the ability to automatically switch to mains power when it is available, so it would be great to just wire it to all the lights and a couple of plugs.

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    Default Re: Which regulations cover the safety of an alternate supply connected to switchboar

    Is there a SANS / SABS / Building Regulation that covers this? I am out of touch regarding the "bible" used by electricians.

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    Default Re: Which regulations cover the safety of an alternate supply connected to switchboar

    SANS 10142 ed 3 annex P gives detailed information.
    • 1960's 88" Land-Rover Series 2A powered by Isuzu C201 (Thermo King generator motor) (Camping, Fishing, Hunting, Towing, Boat launching, Rubbish tipper, Over landing, 4x4 tracks, 4x4 obstacles, Recovery vehicle, Sunday drives and Daily drive)
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    Default Re: Which regulations cover the safety of an alternate supply connected to switchboar

    Quote Originally Posted by Splitpin View Post
    SANS 10142 ed 3 annex P gives detailed information.
    Thank you!

    This is the part that applies to all my 1.5kva UPS installations:

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    And has been interpreted in a few different ways

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    Default Re: Which regulations cover the safety of an alternate supply connected to switchboar

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    1. What does a typical By-pass switch look like (with integrated earth leakage?) - I don't understand this. Is it explained somewhere else in the standard?
    2. I have seen, and like, a 4-pole main switch (isolator) going across the split in the board.
    3. Would a power-on indicator still be required if a 4-pole isolator is used?

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    Default Re: Which regulations cover the safety of an alternate supply connected to switchboar

    You might get answers on the following forums as well...

    https://powerforum.co.za

    https://energytalk.co.za
    Robert van den Berg

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    Default Re: Which regulations cover the safety of an alternate supply connected to switchboar

    Quote Originally Posted by Jonatan View Post
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    1. What does a typical By-pass switch look like (with integrated earth leakage?) - I don't understand this. Is it explained somewhere else in the standard? the bypass switch is a break before make changeover switch which is manually operated between mains and ups backup. With regards to the earth leakage device, you can utilize a "non over current" earth leakage (cheaper) with a 20amp circuit breaker (over current protection)
    2. I have seen, and like, a 4-pole main switch (isolator) going across the split in the board.
    3. Would a power-on indicator still be required if a 4-pole isolator is used? Yes
    Last edited by Splitpin; 2021/11/22 at 08:10 PM.
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    Default Re: Which regulations cover the safety of an alternate supply connected to switchboar

    Quote Originally Posted by Splitpin View Post
    the bypass switch is a break before make changeover switch which is manually operated between mains and ups backup. With regards to the earth leakage device, you can utilize a "non over current" earth leakage (cheaper) with a 20amp circuit breaker (over current protection)
    The schematic they use for the "bypass switch" does not look like a changeover switch to me, but a changeover switch here does make sense for the time when the UPS down for maintenance or fault.

    Over current protection for the UPS output, when the UPS only has 1.5kVA and own protection and all wiring is 1.5mm2 or thicker, feels like overkill, but easy to add.

    The earth leakage on the UPS output can be tricky due to the internal workings of the UPS. My Victron Multiplus gives me lots of nuisance trips when switching back to grid even though it has an internal relay that supposedly prevents these trips. (Cotek and Meanwell inverters don't give me nuisance trips). If the UPS is not connected to plug points, better to avoid the EL. (Red plug points for double insulated equipment may also avoid the EL)

    If you still need indicators when using a 4 pole main switch, then why only on the UPS side. Surely then you also should have indicator on Eskom side.
    Last edited by Jonatan; 2021/11/23 at 07:24 AM.

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    Default Re: Which regulations cover the safety of an alternate supply connected to switchboar

    Quote Originally Posted by Jonatan View Post
    The schematic they use for the "bypass switch" does not look like a changeover switch to me, but a changeover switch here does make sense for the time when the UPS down for maintenance or fault.​​Exactly what the use is for. It is a bypass switch but the operation is the same as a changeover.
    7.12.2.5 Where an alternative supply is provided to an installation or part of
    an installation as a switched alternative to the main supply, the change-over
    switching device shall disconnect the main supply before the alternative
    supply is switched in. The change-over switching device shall be interlocked
    in such a way that the main supply and the alternative supply cannot be
    connected to the installation or part of the installation at the same time.


    Over current protection for the UPS output, when the UPS only has 1.5kVA and own protection and all wiring is 1.5mm2 or thicker, feels like overkill, but easy to add.
    ​6.7.1.1 Each phase conductor of an installation, live (unearthed) conductor ofan earthed d.c. system, and conductor in an unearthed d.c. installation shall
    be protected against overload and short-circuit currents by one or more
    protective device(s). Each protective device shall have a rated current that
    does not exceed the lowest of the current-carrying capacities of any of the
    conductors of the circuit and shall have a minimum short-circuit rating of
    2,5 kA.

    The earth leakage on the UPS output can be tricky due to the internal workings of the UPS. My Victron Multiplus gives me lots of nuisance trips when switching back to grid even though it has an internal relay that supposedly prevents these trips. (Cotek and Meanwell inverters don't give me nuisance trips). If the UPS is not connected to plug points, better to avoid the EL. (Red plug points for double insulated equipment may also avoid the EL)
    ​6.15.1.1.4 A socket-outlet that complies with SANS 164-2-1 or SANS 164-2-2or SANS 164-4 may be used for the connection of appliances for critical
    application (such as emergency lighting, a deepfreeze, a burglar alarm, dataprocessing
    equipment, or life-supporting equipment).


    NOTE 1 Dedicated socket-outlets are the only socket-outlets that need not be
    protected by earth leakage.

    If you still need indicators when using a 4 pole main switch, then why only on the UPS side. Surely then you also should have indicator on Eskom side.
    Having indicators on both sides will be advantageous. Having them installed on the load side of the 4 pole main switch will mean nothing if it is switched off.
    • 1960's 88" Land-Rover Series 2A powered by Isuzu C201 (Thermo King generator motor) (Camping, Fishing, Hunting, Towing, Boat launching, Rubbish tipper, Over landing, 4x4 tracks, 4x4 obstacles, Recovery vehicle, Sunday drives and Daily drive)
    • Want to need list:2.8TD Isuzu engine transplant, Snorkel, New suspension, 33's on inverted rims, Custom Canvas interior, Winch, Recovery kit and brakes!

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    Default Re: Which regulations cover the safety of an alternate supply connected to switchboar

    Okay, I have read all that already, but I think you miss the irony in protecting conductors against overload when the current source (the UPS, not eskom) is incapable of producing enough current to burn the conductor. The inverters are also not neutral tied to ground. Therefore a 20Amp circuit breaker on the 2.5mm2 wires and an earth leakage detector are pretty surplus . . . . but are always installed to keep the regulations happy.

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    Default Re: Which regulations cover the safety of an alternate supply connected to switchboar

    Quote Originally Posted by Jonatan View Post
    Okay, I have read all that already, but I think you miss the irony in protecting conductors against overload when the current source (the UPS, not eskom) is incapable of producing enough current to burn the conductor. The inverters are also not neutral tied to ground. Therefore a 20Amp circuit breaker on the 2.5mm2 wires and an earth leakage detector are pretty surplus . . . . but are always installed to keep the regulations happy.

    If applicable...bypass the ups, the essentials will still require protection.
    • 1960's 88" Land-Rover Series 2A powered by Isuzu C201 (Thermo King generator motor) (Camping, Fishing, Hunting, Towing, Boat launching, Rubbish tipper, Over landing, 4x4 tracks, 4x4 obstacles, Recovery vehicle, Sunday drives and Daily drive)
    • Want to need list:2.8TD Isuzu engine transplant, Snorkel, New suspension, 33's on inverted rims, Custom Canvas interior, Winch, Recovery kit and brakes!

    "Hierdie Landy het gees." - PhlippieV

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    Default Re: Which regulations cover the safety of an alternate supply connected to switchboar

    Quote Originally Posted by Splitpin View Post
    If applicable...bypass the ups, the essentials will still require protection.
    If the UPS is bypassed, the source of the current is a circuit breaker on the pre-split left side of the board in the diagram

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    Default Re: Which regulations cover the safety of an alternate supply connected to switchboar

    That raises a question - must a dedicated circuit breaker be installed here:

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    Default Re: Which regulations cover the safety of an alternate supply connected to switchboar

    I wish the Solar install companies would at least send one of their installers to get their Sparky Qualification or do a JV with a reputable electrician...

    I hate it when they comment "we only do DC".. I would rather have one "go to" company that service all my electrical needs & maintenance as oppose to hopping around between service providers and each one have to figure out what the previous guy did.
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    Default Re: Which regulations cover the safety of an alternate supply connected to switchboar

    Quote Originally Posted by Jonatan View Post
    That raises a question - must a dedicated circuit breaker be installed here:

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    UPS supply. I would say yes. Also protects the cable to the ups.
    • 1960's 88" Land-Rover Series 2A powered by Isuzu C201 (Thermo King generator motor) (Camping, Fishing, Hunting, Towing, Boat launching, Rubbish tipper, Over landing, 4x4 tracks, 4x4 obstacles, Recovery vehicle, Sunday drives and Daily drive)
    • Want to need list:2.8TD Isuzu engine transplant, Snorkel, New suspension, 33's on inverted rims, Custom Canvas interior, Winch, Recovery kit and brakes!

    "Hierdie Landy het gees." - PhlippieV

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    Default Re: Which regulations cover the safety of an alternate supply connected to switchboar

    Quote Originally Posted by Jonatan View Post
    The schematic they use for the "bypass switch" does not look like a changeover switch to me, but a changeover switch here does make sense for the time when the UPS down for maintenance or fault.

    Over current protection for the UPS output, when the UPS only has 1.5kVA and own protection and all wiring is 1.5mm2 or thicker, feels like overkill, but easy to add.

    The earth leakage on the UPS output can be tricky due to the internal workings of the UPS. My Victron Multiplus gives me lots of nuisance trips when switching back to grid even though it has an internal relay that supposedly prevents these trips. (Cotek and Meanwell inverters don't give me nuisance trips). If the UPS is not connected to plug points, better to avoid the EL. (Red plug points for double insulated equipment may also avoid the EL)

    If you still need indicators when using a 4 pole main switch, then why only on the UPS side. Surely then you also should have indicator on Eskom side.
    Where is your earth leakage installed? We have a lot of Victron installs without any problems.

    The feed to the inverter can not be connected to an Earth leakage. Once you come out of the inverter you then go into main breaker -> Earth Leakage -> Circuits.

    With Victron equipment once it is disconnected from Grid, it will do it's own Neutral-Earth Bonding.

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    Default Re: Which regulations cover the safety of an alternate supply connected to switchboar

    Quote Originally Posted by shaneyake View Post
    Where is your earth leakage installed? We have a lot of Victron installs without any problems.

    The feed to the inverter can not be connected to an Earth leakage. Once you come out of the inverter you then go into main breaker -> Earth Leakage -> Circuits.

    With Victron equipment once it is disconnected from Grid, it will do it's own Neutral-Earth Bonding.
    The EL is on the Multiplus output. Will get get around to sorting the problem one day. It is just something weird where the Victron was a drop in replacement for two other types of inverters that did not give me this problem.

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    Default Re: Which regulations cover the safety of an alternate supply connected to switchboar

    Quote Originally Posted by Jonatan View Post
    The EL is on the Multiplus output. Will get get around to sorting the problem one day. It is just something weird where the Victron was a drop in replacement for two other types of inverters that did not give me this problem.

    Yeah, some inverters don't Break the Neutral connection when the grid drops. AlphaESS is one that I have work with that does this. So there doesn't seem to have any Earth leakage problems but when you install a Victron inverters they completely disconnect and have ground relay that clicks in. We have had some problems where non-protected circuit and protected circuit have a neutral connected somewhere in the house, like in a random junction box or something. Can cause the earth leakage to trip. We just make sure to do isolation tests from the protected to unprotected circuits, it will show if there is a join somewhere.

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