July 3, 20241 yr I'm getting charged a whopping R560 a month for a 3-phase connection. My actual usage is usually around R300 - most of my power comes from solar. I noticed on my bill there's a NOTIFIED MAX DEMAND 50.00 line item, and with a bit of reading I saw some people "downgrade" their Eskom line to a lower amount to lessen the network connectivity charge. So I'm unsure what amount of KW can be pulled from that 50a on a three-phase (I assume it's amps?). Anybody know?
July 3, 20241 yr 17 minutes ago, Brenden_E said: I'm getting charged a whopping R560 a month for a 3-phase connection. My actual usage is usually around R300 - most of my power comes from solar. I noticed on my bill there's a NOTIFIED MAX DEMAND 50.00 line item, and with a bit of reading I saw some people "downgrade" their Eskom line to a lower amount to lessen the network connectivity charge. So I'm unsure what amount of KW can be pulled from that 50a on a three-phase (I assume it's amps?). Anybody know? Yes, it's 50 Amps. So around 11.5kW per phase.
July 3, 20241 yr Author 5 minutes ago, GreenFields said: Yes, it's 50 Amps. So around 11.5kW per phase. Thanks, what calculation did you use to get to that?
July 3, 20241 yr 16 minutes ago, Brenden_E said: Thanks, what calculation did you use to get to that? The peak power is 50A x 230V = 11500W. I think that's about as precise as you need to be for this purpose.
July 3, 20241 yr We can expect that the fixed costs per month will escalate, some people in some towns on prepaid only pay kWh! In my town for example, that 50A three phase would cost R1,458 ex VAT… A lot of old era homes had enormous electricity supply, far more than the home needs unless you also run a welding shop. Downgrading connection and even changing from three phase to a small single phase is possible but it will all depend on your setup, how much solar, etc. If have big solar, then split up that you have a minor public board and a battery between it and your existing board with most loads.
July 3, 20241 yr Author 14 minutes ago, macafrican said: We can expect that the fixed costs per month will escalate, some people in some towns on prepaid only pay kWh! In my town for example, that 50A three phase would cost R1,458 ex VAT… A lot of old era homes had enormous electricity supply, far more than the home needs unless you also run a welding shop. Downgrading connection and even changing from three phase to a small single phase is possible but it will all depend on your setup, how much solar, etc. If have big solar, then split up that you have a minor public board and a battery between it and your existing board with most loads. Are they paying R1458 just for supply? That seems...excessive 😐 Once downgraded at least it should go down to R250 p/m. But yea, eventually it becomes so expensive it's worthwhile to go completely off the grid.
July 3, 20241 yr 10 hours ago, GreenFields said: Yes, it's 50 Amps. So around 11.5kW per phase. AFAIK demand is always a kVA value. Thus it will be 50kVA. Amps/kW are not really used as it will vary based on PF. kVA is fixed at a constant voltage. Edited July 3, 20241 yr by Scorp007
July 4, 20241 yr 21 hours ago, Brenden_E said: Are they paying R1458 just for supply? That seems...excessive 😐 Once downgraded at least it should go down to R250 p/m. But yea, eventually it becomes so expensive it's worthwhile to go completely off the grid. R1458 just to be connected. My town has charged high availability for ages, but they do charge lower kWh. It is a clever strategy to try and compete against solar. Eg at my factory we now pay R441/kVA for highest half hour kVA but 144c energy charges. So on a 300kVA peak demand, the cost before one kWh is R132k per month…. The only way to beat that is to add storage to solar and have an inverter that caps your grid draw at say 100kVA. That battery, ignoring any increased solar use, generates R1m a year in direct savings. It also means solar runs 100% during loadshed. I haven’t used diesel since September 2023 Edited July 4, 20241 yr by macafrican
July 4, 20241 yr 30 minutes ago, macafrican said: R1458 just to be connected. My town has charged high availability for ages, but they do charge lower kWh. It is a clever strategy to try and compete against solar. Eg at my factory we now pay R441/kVA for highest half hour kVA but 144c energy charges. So on a 300kVA peak demand, the cost before one kWh is R132k per month…. The only way to beat that is to add storage to solar and have an inverter that caps your grid draw at say 100kVA. That battery, ignoring any increased solar use, generates R1m a year in direct savings. It also means solar runs 100% during loadshed. I haven’t used diesel since September 2023 This way has been in place for decades in factories to lower that max demand during that 30min. That's why energy management and PF correction was a good business to be in for long. Controlling processes can also make a huge dent in many instances. At a saw mill I worked I put in systems not to start huge frame saws at the same time in the morning. Also put in many cap banks for all 3 ph motors above a certain size. Not many controllers were available in the 1980s like today.
July 4, 20241 yr Author 20 hours ago, Scorp007 said: AFAIK demand is always a kVA value. Thus it will be 50kVA. Amps/kW are not really used as it will vary based on PF. kVA is fixed at a constant voltage. For working out the Max Kw how does that affect the equation? I'm unfortunately ignorant of the various electricity units.
July 4, 20241 yr 1 hour ago, Brenden_E said: For working out the Max Kw how does that affect the equation? I'm unfortunately ignorant of the various electricity units. KW=1.73*400V*Amps*0.7 One can assume the power factor as 0.7 It will be 1 for resistive loads like oven, kettle and geyser. If the power factor is 0.7 then kW=37
February 3, 20251 yr On 2024/07/03 at 12:28 PM, macafrican said: We can expect that the fixed costs per month will escalate, some people in some towns on prepaid only pay kWh! In my town for example, that 50A three phase would cost R1,458 ex VAT… A lot of old era homes had enormous electricity supply, far more than the home needs unless you also run a welding shop. Downgrading connection and even changing from three phase to a small single phase is possible but it will all depend on your setup, how much solar, etc. If have big solar, then split up that you have a minor public board and a battery between it and your existing board with most loads. I have a 40A 3 Phase connection - my basic line charge before any electricity is R6800
February 3, 20251 yr 1 hour ago, GaryS said: before any electricity is R6800 Oh my goodness - this is madness!! 😰
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.