I know it's late and the lap dances are still open , so i will wait till tomorrow for any replies . Does anyone have resistance per meter tables for steel armour 90degree thermosetting ,can't find it anywhere . Ta
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
Determine the minimum size of cpc for the circuit giving consideration to; Disconnection times Thermal Constraints?
Here is what I have worked out so far for the circuit -
Ib=p/(Ulx√3) = 12000/(400 x 1.732) = 17.32Amps
From Table B6 I selected a C20 which has a max Zs of 0.87 Ω
20>17.32...
Hello Can I just confirm that if 90 degree cable is used in switch gear that is only ratted at 70 degrees then you use the 70 degree tables to find the maximum current carrying capacity in this case Table 4D1A
I ask this as I carried out an EICR and found 4mm 6491B cable run in trunking...
Also just revising: trying to apply a rating factor for insulation on a cable calc. Just in theory, it's not for an actual job.
The cable will be clipped direct to joists above ceiling and is covered in >100mm thermal insulation. I cannot find the correction factor for insulation. Advice please!
hi folks, does anyone have a copy or link to the most recent maz zs tables? ive only got green book and know they've been updated, was it 10% extra roughly. i used to have a link saved on my phone but i must have deleted it by mistake, thanks.
Hi guys,
Might be a silly question but getting really confused.
Table 4D5 for choosing cable size for different installation methods, does this already have de-rating factors applied for the different methods? If so, then if you calculated your current capacity using specific de-rating factors...
Hi there! I have successfully completed all parts of my coursework for level 2 and 3 2365, bar one notorious question:
A trunking run within the electrical switch-room area is to contain the following single-core thermosetting stranded cables
35 x 1.5mm2
25 x 2.5mm2
12 x 4.0mm2
10 x 10.0mm2...
Hi,
I was calculating volt drop today using xlpe armoured cable, 3 core, single phase. Table 4E4A pg 373. I am using 3 core cable but on single phase, so i would assume column 3 for single phase. I was told by the tech helpline although the cable is being used for single phase that column 4...
Hi,
I have a table lamp that I love but it only allows bulbs up to 50 watt although the shade is large and open so not really a fire hazard. I have been using halogen bulbs to the equivalent of 70 watts (I think they're around 42 watt but I threw the box away) but they only last about a month...
Hi all hope all is well and nice layout for the forum, like it. Been flicking through the OSG and notice that in table 7.1 (max cable lengths for final circuits) that there are no cb's or rcbo's rated above 40A. Is this because they feel like no ones interested in anything above 40A, am i...
i am trying to install a 1no1nc push on off led switch in my car to intercept my power antennae. it has 5 terminals with red, white, black and 2 green wires. the 2 green wires are marked NO and NC. i think the red is marked+. cannot see any markings for black and white wires.it did not come...
I've recently done a C&G 2396 Electrical Design Course and unfortunately the tutor who taught the course did so for the first time and in my opinion didn't do a good job of teaching the material. I'm now doing my revision for an exam this Thursday and trying to make sure all the formula I use...
Edited: sorry of course Ze should be added to the post below, Table 41.3 is for comparing Zs.
Hi, it is my understanding that Table 41.3 of BS 7671 should be used for comparing the tabulated values with the resistances of:
1) the line conductor at 70 degC;
2) cpc at initial temperature, as...
Hello everyone,
This is my first post, so please bear with me. I am trying to work out how the motor to my table saw is wired. I bought it second hand and I think the previous owner has messed with it. One of the brush holders had been forced in and was touching the commutator. I am wondering...
Hello all
I have a quick question on using my on site guide. I've found this forum fantastic for help so far. It's quite simple.
I have a question which asks what the voltage drop for a single core 6mm² 70⁰c insulted cable for a single phase circuit is, enclosed in conduit.
Page 151 of the...
Eh up :)
We all know about the duff max Zs tables in the OSG (Table B6) and GN3 (Table A4)... in fact, I've only just recently updated my GN3, and I'm pleased to say they have reprinted it and it now has the correct tables in.
I've noticed in my (early-purchased, with dodgy table B6) OSG that...
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The heading of table 41.3 says it shows " max earth fault loop impedance Zs for Circuits Breakers..... giving compliance with 0.4s disconnnect time of 411.3.2.2 and 5s disconnnect time of 411.3.2.3."
411.3.2.2 is for final circuits not exceeding 32A. 411.3.2.3 is for distribution circuits and...
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