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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 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...

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, 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, A contractor is building two adjacent houses, each house has a pool, the two pools are formed of one large reinforced concrete pit with a reinforced concrete wall in the middle. Once the ground works are complete, a fence erected along the mdian wall will separate the two pools...

Hi, I'm Electrical so forgive the question if too dumb. I'm working on a residential project where some apartment windows need to be drenched to avoid the risk of fire coming inside the unit from a source adjacent to the unit (the building has a funny architecture). Now a question is coming...

Hi, We were asked to demonstrate that our scaffolding will be sufficiently away from a 33kV overhear bare conductor wire. I don't know which standards you use but in Australia we use AS 7000. That standard states that the insulator swing and conductor blow out can be accurately calculated as...

Hi, I just want to understand the terminology if possible. When you have an 11kV vacuum based HV metal clad switchgear, i am being told that in case there is an arc inside the cubicle, it comes out from the back, then by the time it is out it is no longer hot to be dangerous. However, if you...

Hi, I have a swimming pool with metal access ladders for swimmers to use. The pump room is far away. The only electrical equipment in the swimming pool are 24V submersible lights. Is there any requirement for "earthing and bonding" of the metal ladders that the people use? It can never become...

Hi, The data we have on a welding machine is as follows: Lincoln Power Wave - 3 phase 230/400V 60% 44A 100% 33A I'm assuming the 60% and 100% are the duty cycle. Q1: is it normal that the current in 100% duty cycle be less than 60%? Q2: what is the required rating of circuit breaker to...

Hi, I have little experience at HV side. Usually for my 800 kVA 11kV/400V 4% Ucc transformer I would calculate the fault at the LV side assuming an infinite bus at the primary, giving Isc = 800/3/230/0.04 = 29 kA However in this particular instance we need to calculate the actual fault not...

Hi, Quick question please, if a transformer has 11kV at primary and 415V at secondary, why is it wrong to say that an earth fault of X amps on the LV side is equivalent to a current of: Y = X * 415 / 11000? Why doesn't the earth fault follow the turn ratio? Thanks.

Hi, I have an application where a static converter takes at the input 230V AC 3 phase 50Hz and produces at the output 270 V DC. The converter does not have an isolating transformer. What I know that the 270V DC will be cabled into an equipment that has its body earthed. My question is: can you...

Hi, I have an LV load that is 1,200 meters away in underground cable distance from the point of supply. It is a 3 phase LV load with 30A on the worst loaded phase. There is an RCD protection at the origin of the cable at the point of supply, to avoid running an earth cable and to mitigate...

Hi, A number of devices from the USA have different voltage than in Australia. The guy has his own transformer from 415V at the primary side L-L to 208V at the seconday. There is a distribution board at the secondary taking tge one output fron the transformer and distributing it via single...

Hi, A 100A "High Rupture Capacity" fuse is supplying a tariff meter. The curves of the 100A fuse and an upstream 160A circuit breaker set at 140A, when shown with tolerance/band, are touching at the long term delay section. The curves of the 100A fuse and the 140A CB, when shown as...

Hi, Can someone please advise on which voltage the single phase voltage drop is calculated? The application is simple: we have a cable 100m long. It is a 3 phase multi-core copper cable with cross section 25mm² per phase and neutral. The voltage is 230/400V 50Hz. From page 87 in the following...

Hi, Someone wants to connect an HV copper cable to an HV aluminium cable and is asking if there is an amalgamated junction box that can be used for this purpose without corroding the cables on the long run. If you know of such connector can you please propose a make/model? Many thanks.