80% rule

[oldtimer]

In my work we had our 5 year PIR and we were issued with the test results, There was 2 figures on the sheet one was the actual ELI and the other was the max ELI.

So I compared it and found that the max ELI figure was taken from the tables in the 17th edition book.

My question is that the onsite guide tables have the figures corrected to the "rule of thumb" figure of 80% so when I drew this to the attention of the testing company they said they complied with the 17th

Can someone clarify the correct use of the 80% rule of thumb figure.

 

[Mac]

Hi and welcome to the forum

 

[ezzzekiel]

depends on test sheetyour usingand if it asks for max value or corrected value, if its max value then put it in from bs7671 but check it meets adjusted calc also

 

[trebor]

In my work we had our 5 year PIR and we were issued with the test results, There was 2 figures on the sheet one was the actual ELI and the other was the max ELI.

So I compared it and found that the max ELI figure was taken from the tables in the 17th edition book.

My question is that the onsite guide tables have the figures corrected to the "rule of thumb" figure of 80% so when I drew this to the attention of the testing company they said they complied with the 17th

Can someone clarify the correct use of the 80% rule of thumb figure.

The majority of test result sheets have a column for the max tabulated Zs figures from BS7671 and a second column for measured Zs

The 80% rule only applies to non temperature corrected tables such as BS7671, both the OSG and GN3 plus NICEIC tables are already corrected by 1.20 for conductor temp and 1.04 for ambient air temp thus the 80% rule does not apply

The reason the BS7671 max figures are used is so that correctuion can be made taking into account any differing conductor and air temperate at the time of testing which the 80% may or may not cover

 

[Spudnik]

Although you record Max Zs from the 17th, your readings you record should be less than 80% of this value.

 

[quince80]

i believe guidance note 3 will have the values at 80%. saves a little time with the old calculator.