parallel | Page 7

parallel

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  1. 4

    Parallel paths headache.

    Hi guys, I've spent the last few weeks reading through the site and have got to say I'm very impressed with the patience and knowledge you all have. This topic has been discussed and i'm sorry for bringing it up again but I would still like your opinion on the way I test and record my Zs...
  2. M

    parallel swa submain

    Hi I am considering the possibility of using 2 unused and existing 95mm 4core aluminium cables in parallel to feed a new submain distribution board I wondered if any one else has done similar and may be able to reassure me on the practical and/or technical implications the length of run is 130m...
  3. M

    Balanced strings in parallel

    I am designing a 2.3kw on roof pv sytem at the moment but am having trouble sizing an inverter, for 15 modules in 3 parallel strings, so the easy option is to go for 14 mods in 2 strings. The question is could the strings be imbalanced? ie 1 string of 8 and 1 string of 7 in parallel, thus...
  4. E

    two inverters connected separate or parallel

    I have two inverters wired to two strings. Do I need two separate wires from each inverter to an individual mcb. Or can I dual up the supply so only using 1 isolator at the generation meter end. I will still have 2 isolators in the loft adjacent each inverter. Or is it best practice to run 2...
  5. V

    total resistance of a parallel circuit

    Hi, Question- Why is the total resistance of a parallel circuit always lower than the lowest resistor? I feel i have read lots on parallel circuits and googled it many times but still cant figure it out. The four answers i have to use are: A=The current is the same across each resistor B=the...
  6. D

    Parallel Battery Discharging.

    Does anyone know the best way to discharge 2x12v batteries at an equal pace? We are currently using 2 diodes, one for each battery to help them discharge equally but the diodes see to get extremely hot and also sometimes dont seem to work too well. Is there anybody who knows of a better method...
  7. G

    Lighting circuit with PIR in parallel with Switch

    Hi, my landing does not get much natural light and was thinking of adding 2 PIRs and also keeping the current light switches. One PIR in the hallway on the groung floor and one on the landing, can anyone see any problems with this? Thanks
  8. FatBob

    Using MCB's in parallel to give local isolation

    This installation has a very old DNO metal fuse box with a hinged lid, which may or may not open in one piece. The DNO's meter feeds 2 x 63A MCB's in a 2 slot CU. Can I feed a Henley block with both line connections from the 2x63A MCB's, thus using it as a local isolation switch? The...
  9. D

    Zs testing

    Hi I have just tested the Zs on my ring final circuit... i got the readings 0.25, 0.32, 0.47 and 0.52 there are more but the readings were basically between 0.25 and 0.52 Ze is 0.11 and r1+r2 is 0.35 i get the same readings either at the front or the back of the socket so with the test...
  10. D

    batterys in series

    hi every one just a quick one if i connect 2 x 12v battery's in series to get a 24v supply what happens to the Ah of my batteries? thanks in advance Mike
  11. J

    method of finding R1+ R2 of circuit

    Why is Zs-Ze not a approved method of determing the R1/R2 of a circuit
  12. D

    RCD's in parallel

    Hi, Working at a house (TT system) and a new build office/garage is to be built. House has split load RCD board. 1. Should i use 1 of the spare ways and feed the office with a sub-main. or 2. Use henley blocks and take the supply from meter tails. Option 1, will mean if the house trips then...
  13. A

    excessive earth loop impedance on final circuit

    Hi. This seems like a newbie question but please help. Received the test results with an 'excessive earth loop impedance' on one final circuit. Circuit originates with a 32A MCB and serves 10 socket points. Wiring is 2x2.5mm live, 2x2.5mm cpc. Max Zs = 0.72 Ohm. r1 (line) = 1.68, rn (neutral) =...
  14. J

    Pros & Cons of Wiring in Series & Parallel?

    Anyone care to take a stab at it?
  15. Jay Sparks

    Cables in parallel formula

    Hi Guys Quick one for you. A cable that is 25M long and has a resistance of 2.3 m ohms/M ( milli ohms per metre ). A second Identical cable is to installed in parallel with this conductor. What is the total resistance of the two conductors connected in parallel? 1st conductor: 25 x 2.3 =...
  16. ringer

    Final Circuit conductor sizes in OSG 8.2

    Referring to pages 158-159 in the OSG Table 8A Type, OPD(A) A1 Ring, 30 or 32 .......etc 8.2.3 Conductor size ....The as-installed current-carrying capacity Iz so calculated must not be less than: 20 A for ring circuit A1 Am I reading/interpreting this correctly when I say...
  17. N

    Help Please with Parallel connection affect on Resistance!

    Hi i have this question that i am not sure of the answer. Can you please Help? State the effect on measured resistance when cables are connected in parallel. Answer: The resistance value will be reduced. For example in resistance for Zs testing in ohms has a measured value that is...
  18. A

    Parallel feeder cable Question

    Hello All. Not been on here for a while, hoping you guys can help me with this one. We installed 185mm single copper core aluminium armoureds (2*185mm per line conductor each run 170m) to an MCC feeder. The intend was to use the aluminium armourings as the main CPC. My question is, how can i...
  19. G

    Pir sensors for flood lights, parallel wiring 2 sensors to one load

    Hi all, Is it possible to wire two PIR sensors in parallel in order to give two beams of coverage with just one flood light as the load. Have you done it? I am concerned that if one sensor activates, 230v would get onto the output of the other without the other having been activated. I have...
  20. S

    Power Supply?- Installing 12v Dowlights (MR16) in Parallel

    Just a quick one to get a feel for what other sparks are doing when installing 12v downlights into kitchens etc (in existing properties, not newbuild). I have a customer who wants me to install their new (9x) downlights at the cheapest price (no suprise) so as this has an impact on the amount of...

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