Discuss R1 + R2 expected readings in the UK Electrical Forum area at ElectriciansForums.net
Buzz - congratulations my friend! That's the clearest and most coherent post you have ever made on this forum ;-)say we have R1+R2 = 2.35 ( hypothetical figure )
R2 = 1.67 x R1 ( 2.5/1.5mm )
so R1 + ( 1.67xR1 ) = 2.35
( 2.67xR1 ) = 2.35
R1 = 2.35/2.67 = 0.88
R2 = 2.35 - 0.88 = 1.47
( or R2 = 1.67 x 0.88 =1.47)
I am doing eicr tests so it will be just a rough guess to how much cable has been used for calculationsNo don't use that table, it;s ok for reference but you need to use the resistance tables, google them. The whole point being is to work out for yourself the expected measurements as a reference point. When I put in a RFC I know how much cable I have used so say it was 63 m I calculate off of that. Those charts are sort of end user you need to get into the mechanics of how they made those charts.
And thats all the op needs, is a reference point. If you pay for the procerts app, they use the same resistance values in their tables to use as a quick calculation onsite.No don't use that table, it;s ok for reference.
If you had a Ze of 0.75 ohms and an R1+R2 of 1 ohms for a circuit protected by a B16 breaker, would the supply disconnect in under 0.4 seconds under fault conditions?How much would yous let the reading be over before you were to investigate it further as obviously a number of things could effect readings but for like a radial socket in a house on 16amp carrying 6 sockets say the reading was just over 1ohm (just a random figure) would yous want to investigate that further for been high reading
In this case I respectfully disagree, as the OP is not just 1st fixing and dead testing, he is carrying out EICR inspections. A good understanding of electrical theory is very important to determine what is safe and what isn't.And thats all the op needs, is a reference point. If you pay for the procerts app, they use the same resistance values in their tables to use as a quick calculation onsite.
Okay, if i had a radial circuit wired in 6mm/6mm swa and the measured R1/R2 was 0.16ohms. What table or resistance value would you personally use to calculate the length of that circuit as a reference point, and what length would you calculate?In this case I respectfully disagree, as the OP is not just 1st fixing and dead testing, he is carrying out EICR inspections. A good understanding of electrical theory is very important to determine what is safe and what isn't.
I think we have ended up slightly at cross purposes. I have no issue with anyone using OSG, BS7671, Pro Certs, or any other reliable reference of the resistance of copper in order to work out expected R1+R2 values.Okay, if i had a radial circuit wired in 6mm/6mm swa and the measured R1/R2 was 0.16ohms. What table or resistance value would you personally use to calculate the length of that circuit as a reference point, and what length would you calculate?
Since you disagree with using the onsite tables and the procert one, im curious what you would use?
Two things concern me about this thread:
1. The OP is conducting EICRs but not doing any live testing.
2. The OP is conducting EICRs without knowing basic things like how to calculate R1 and R2 values.
3. Sorry there is no third thing
Two things concern me about this thread:
1. The OP is conducting EICRs but not doing any live testing.
2. The OP is conducting EICRs without knowing basic things like how to calculate R1 and R2 values.
3. Sorry there is no third thing
For EICR purposes, the two things that come to mind are how close the calculated Zs is to the limit for the device, and a sense of how big the property you are in is and whether a reading seems plausible. The more you do the easier that gets.All I was wondering is if they was a table about I could use as a guide for r1 r2 readings so I know my readings are correct or slightly high and I need to do abit of further investigation on circuits
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