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@3DDave thanks, you are right, and for the first link you sent I did contact SAL and asked them if the filter is in t he SDD 'dimmer' or if i just get the SFI downlights then they will include a filter as well: they said the lights will be flicker immune even on manual ON/OFF switching not...

@stevenal thanks for your reply, there are a lot of apartments in the same building that are not experiencing any flickering. Also these are LED lights not incandescent: the incandescents back in the day used to have 'thermal inertia' to ride through frequency canhed, for LED: it all depends on...

Hi, I got 2 other videos: Video 1 Video 2 This is high frequency and different in kind from the first flickers which appear to be voltage drop issue due to high impedance / loose connection. I have a feeling it is due to the controlled-load frequency that the supply authorty delivers in the...

For the loose wiring termination, am I correct in understanding it this way: the loose connection is causing a high impedance contact with the power supply, therefore reducing the applied voltage. With the reduced voltage: the capacitors in the ballast do not have sufficient time to charge hence...

Hi, What can be causing these lights to flicker? 1: https://www.dropbox.com/s/9wyc7vck7n7dkex/Defect%20%231%20-%20garden%20lights.MOV?dl=0 2: https://www.dropbox.com/s/cj6or3x1awmdhnu/Defect%20%232.A%20-%20garden%20lights.MOV?dl=0 3...

Hi, Can you please put a link to a whitepaper, forum or similar regarding the requirements for protecting electrical and control cabling in a fuel refinery? Something like: use X kind of heat shrink as the cable enters the conduit, then use cable glands type X as the cable enter the equipment...

Hi, We have an expensive piece of equipment that can withstand only about 4,000,000 A²s let through energy. There is no circuit breaker fast enough to clear a fault that quick, so we would like to place a fused isolation switch right next to that device. The semi-conductor fuses should be...

I got these formulas but wonderinig how to use them in HV: Z = impedance per phase ULN = phase to neutral voltage ULL = sqrt(3) x ULN 3-Phase fault: Ik = ULN / Z Earth Fault: Ik = ULN / (Z+Z0) and just for the record 2-phase fault: Ik = ULL / (2 x Z) which I think is easiest to understand...

If anyone else is going to post, I appreciate that it is actually the formula how to calculate the 3 phase fault in HV from the earth fault thank you.

@FreddyNurk You are correct, I am not designing for fault withstand capacity I am designing for grading. I know, the inclusion of the upstream impedance will reduce the fault level to its actual value not the theoretical maximum based on infinite upsteram bus. Yes I have your same assumption...

I want to calculate the short circuit at my main switchboard. I have the transformer's data (2MVA, 6%) and I have the network upstream fault so I use: 1 / MVA system = 1 / MVA utility + 1 / MVA transformer I presume that's correct, right? Only one more thing: for the utility they gave me the...

Thanks we decided to use Flexible Busbars.

Hi, A 3 phase cable with 240 mm2 cross section for each of the phases is required to connect to a 160 A circuit breaker. The cable is too large (2.2 x the cross section of AWG 0000 (4/0)), and the terminals on the circuit breaker do not fit. What accessories would be a good 100% legit (not...

Hi ScottyUK No we are not thre yet, RCD is required for many applications (AS 3000 section 2.6.1) but not for all applications and not for all concealed wiring. But I think the question is not only realted to concealed wiring, the question is whether or not the earthing of a metal part is a...

Hi rtronics, yes precisely 5.4.6. the 0.5 ohms is for the bonding conductor itself not for the whole resistance of the bonding conductor + resistance to earth of the metal frame. the maximum resistance of the main earthing coductor connecting the earh bar in the main switchboard to the main...

Thank you waross for the description of the various methods of testing. It seems that we are after an earth continuity test. With regards to the RCD/GFCI: 1. The risk of gettinig stuck is mitigate in Australia by mandatory regular testing of the operation of the RCD/GFCI. This includes testing...

Hi waross, Thanks, two questions please: Q1: this inspector is not an AHJ, he was brought in as extra checking. So forgetting NEC and AS 3000 for a moment, given that there is RCD/GFCI protection, would there be any hazard on the tenants in the future based on law of physics not on...

Hi, An Electrical contractor is installing wiring inside the apartments in a multi-dwelling apartments building block. The job is in Australia, based on AS 3000. He is not using the boxes in the wall. He is just running the cable from the unit/apartment distribution board to the power outlet...

Hi Guys, Just to let you know the AHJ has reviewed the issue and approved it, requiring only that the bonding at the pools be removeable for future fault finding, and a label at the point of supply indicating the additional bonding. Best Regards.

Thanks HCBFlash Is there a maximum vertical drop length after wich bends should be used, something like a rule of thumb?