Hi all,
Why is there no max Zs value for a 45A type B breaker in table 41.3 of 18th edition? What value should be used as max value on schedule of test results?
Cheers.
Where can I find the max Z's value for a BS3871, type 3, 32A MCB?
Iv had a look through BS7671 and done some searching online but I cannot find it. IV found some tables with listed Zs values for a 3871 but I have no idea where they originate from or how old
right I get a bit confused with working out the Tabulated values (I am training and have exams tomorrow for Initial verification) on the Ze and Zs anyone on here what to explain how this works on the earth loop impedance, please can someone explain what I am overlooking ?thanks, Jules I...
Given that Amd3 reduced max Zs values slightly what is everyone coding if a measured reading falls between the pre Amd3 value and the post Amd3 value. Failure to meet disconnection times would normally be a code 2, but a code 3 seems appropriate here......maybe a note to explain? On E-certs it...
Hello.
I'm in the final stages of completing my electrician course, and I find myself confused (again) by EFLI.
In the textbook provided is this:
Uo 230V
see below for each circuit.
Calculate the maximum Zs for each circuit:
Complete the table.
The answers given in the textbook are said to...
So I've been told by the NICEIC not to use the 80% rule for max Zs (even though that's the table provided on the inside of the cert books). They want me to use the 100% values from table 41.3 in the BYB. Not a problem.
However I can't seem to find a table for the BS EN 3871 MCB's in there...
Hi all,
Repairing a 2kw convection heater in our workshop office and I'm getting zero resitance on the min/max dial at any setting. What is the value for min and max as need to lever the spacing to get a resistance but don't know if it's too much or too little
Cheers
Hi,
I was doing my r1+r2 tests on a lighting circuit yesterday in a 6 bed house over 3 floors. Approximately 20 points not including switches. Mainly pendants but some light bars etc and almost all LED or low energy halogen type bulbs. Closed circuit r1+r2 values range from 0.88 on ground...
Can anyone help me understand Zs values.
In the On-Site-Guide page 60 Table 7.1 under the heading Maximum cable length, it states if
Zs < 0.35 ohms for a TN-C-S system
you can have a cable length of 107m
In BS7671 page 58 Table 41.3 it states the
Maximum Zs for a 32A CB to operate within...
Hi all,
Quick question when doing r1+r2 testing wether its a new install or a EICR, is there a table to show maximum readings we should be getting? Or is it a calculation?
Thanks in advance
Luke
I know that the 80% values are applied in regards to operating temperature etc but NIC paperwork asks for the max permissible values of bs7671.
So when do you guys apply the tabulated values?
I've done commercial condition reporting in the past with a company that used their own test sheets...
Hi for a ring circuit, is there any need to measure and enter R1 + R2 values on a schedule of results ? Because an r2 value is already measured (together with r1 and rn). If I needed a ring R1 + R2 value to calculate ZS (although i would find ZS with a socket tester so really no need; but if I...
Hi there,
I have a ring circuit where the Zs reading taken is higher than maximum allowed values.
the circuit is protected by a 32a RCBO type C device, Zs = 1.43.
I have currently have tightened terminations which has brought it to its current value.
as i have been out of the game for a while...
Iv been given the scenario:
6 circuit earth fault loop impedance values were recorded. Each circuit has type B cb.
referring to the maximum values, show by calculation if these values are acceptable.
so I can't do zs =ze+R1/R2 because they've not provided me with ze.
doing some research it...
Hi all,
Only recently joined the forum, and thought i would get some views on the following.
Just wondered if anybody has had the following issues when fitting a new ccu.
Recently completed a rewire, including new new metal ccu, completed all dead tests ok, however upon live tests i got high...
i am testing 4 flats in the one close, high rise flats were being brought down next to them so tennants have been moved out for a few months, and its freezing cold in glasgow right now, when testing the house ring which is wired through conduit i am getting between 30 - 50 mega ohms going...
Hi,
I am getting a reading of Live to Live = 195 MOhms
Live to Earth = 0.75 MOhms at the distribution board I am working on a Highway depot.
Are these acceptable values?
If not... what do I to?
Thanks,
Lasowski101
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