If you install a T2 surge arrestor in a domestic property, do you connect it directly after the main switch, using a 16 mm wire and no fuse or,
do you install a 32 amp mcb and wire it with 4 mm wire?
If you install a T2 surge arrestor in a domestic property, do you connect it directly after the main switch, using a 16 mm wire and no fuse or,
do you install a 32 amp mcb and wire it with 4 mm wire?
Normally a surge arrestor has 125Amp protection rating requirement .Some are different.
If it was 125Amp rating and my main switch is 80Amp protection , I would leave it at full rating.
If you stick a 32 Amp C/Breaker in it may trip on a surge that it is trying to clamp and then letting the rest of the surges through which kind of defeats the object.
I would rather let the surge arrestor take the surge to earth and if it is a big surge trip the 80Amp supply - That way I ensure the client is disconnected from any further surges .
The big unit we install in the factories have 125 amp fuses and wired accordingly.
I have decided to mount the unit next to the main switch and using the busbar at the top to feed the L of the surge arrestor which will have a 16 mm supply cable, which reminds me I must check the main switch is not identified line and load, because the line will be in the bottom. I will also fit a tag on the main cable identifying line and load.
I am using a little T2 10 ka CBI unit.
I am told the surge arrestor will not carry any load it is a transient over voltage protective device.
This is another topic which we should discuss in a lot more detail. I normally contact the specialist in JHB, but he has retired and only works as a consultant now.
The manufacturer indicated that no circuit breaker is required and a 16 mm wire connected to the top of the surge arrester and a smaller wire for the earth (no size indicated , so we will use a 6mm) would be the preferable way to wire it. Than k goodness I have a busbar on the top of the breakers which are not on earth leakage, so installing a 10 or 16 mm bridge across the top should be fine. The supply breaker is 60 amps.
I think it might be batter to get it in writing.
Victor - Knowledge is a blessing or a curse, your current circumstances make you decide!
Solar pumping, Solar Geyser & Solar Security lighting solutions - www.microsolve.co.za
Would you install a surge arrestor at the main DB and the essential supply sub DB (after the inverter)?
I am wondering if it would be necessary after the inverter, considering the inverter offers a pure sine wave and should have some form protection built in.
It is a requirement to install DC surge protection in a combiner box for the solar power.
I would say no as you say the inverter does all that![]()
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