discrimination | Page 2

discrimination

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  1. A

    Discrimination

    I am using Amtech software and I am having trouble trying to achieve discrimination between a 100 amp SPN MCCB (Schneider TM-D) and a 200Amp BS88 in a TPN Switch Fuse. Anyone else had this problem and know how to sort it. I can only achieve discrimination if I change the mccb for a 63 Amp one...
  2. P

    Problems about IDMT relay

    Today i found that there are two questions about IDMT relay which i dont know how to answer. 1. What will haggen if electrician forget to insert the "plug" in the IDMT protection relay? 2. Discrimination is important in electric circuit protection. Please tell me how to apply the plug settings...
  3. J

    discrimination conundrum

    Hello to all, Have just completed an EICR for a client of mine who would now like me to do the remedial work. I've hit a problem with the design of the job. Part of the work will involve a new CU with RCDs and possibly a couple of RCBOs The CU is remote from the meter position and is fed via...
  4. mattg4321

    Standby generator wiring

    Hi guys, after some advice for a job currently ongoing. I'm fairly inexperienced when it comes to generators, trying to decide whether or not to take this on. We are currently wiring a domestic new build (mostly!) property (including 4 separate buildings, all with lightings/small power). 90%...
  5. L

    No discrimination, no problem???

    Had a discussion with a mate about this upcoming job, scenario is as follows - TNCS to dwelling, 40a MCB @ DB1 (not RCD protected/not required) feeding 6mm2 3core SWA running through loft to outside wall (not buried in walls or ground anywhere) to DB2 (lean to timber shed attached to dwelling)...
  6. C

    What does provide discrimination?

    Hi all. I am finishing my level 3 in electrical installations and as such, I have tried to explain this to a friend. So much so, that now he's got me doubting myself. He's powering his garage which is attached to the main house. He's also providing the circuit supplying the garage with RCD...
  7. J

    MCCB incomers on paneboards

    Hi I have a question which I am sure can be answered by the chaps on here in seconds. Why do panelboards often have MCCB's as incoming devices over isolating switches? I understand this can be useful if the PFC is high at the board and an incomer like this can protect outgoing devices. Is this...
  8. L

    RCD Discrimination Help

    I am not yet fully qualified and this is not a job I am going to take on so have passed it onto a qualified electrician , but out of interest I would like to understand it. Domestic TT. CCU in house feeds (SWA) to a garage CCU (with an independent earth rod). Now someone has taken the feed from...
  9. rich.250

    Rcd discrimination

    Hi guys. Called to very strange call out today, cannot get around why and what exactly is going on. Heres the set up, TT system with a rod at 51ohms. 100mA s type rcd upfront feeding 2 units. A switch fuse to a submain for the main house db and single 30mA rcd board feeding the rental part...
  10. F

    Discrimination

    We have a test bench in one of the buildings that I can't attend at mo so trying to diagnose over phone not good I no but we have a rcd socket on a work bench were we plug in to test faulty appliances that have been sent back to the company no why does it sometimes trip the breaker at the board...
  11. S

    Discrimination

    My boss has asked me to fit some MCB's that i feel doesn't offer enough discrimination, a 63amp c type mcb feeding a submains then out that submains is a 63amp b type feeding a circuit. is this enough discrimination?
  12. L

    Garage Discrimination help

    Hi, I'm looking for some help on wiring my garage at home. I'm currently training to be a electrician and I'm going to wire this up. 2 x 13a sockets on a radial (2.5 t&e, 20a mcb 2 x 40-60w light plus switch (1.5 t&e, 6a mcb Main garage fuse is 63a rcd My main concern is where and how do I...
  13. F

    Amtech and Fault Current and Discrimination

    Hi All, Having done my model for Amtech LV. I have noted that when Descriminating between two breakers the Pscc is taken at the load end of the circuit when analyazing discrimination between breakers. Example being:- The discrimination limit between upstream device Q1 and downstream device...
  14. J

    rcd discrimination, funny example

    Working on a big house belonging to a boss of a billion £ building company There is a dual rcd in the house feeding a dual rcd in the poolroom ,my boss said to provide two double sockets for the builders/site and gives us 2 rcd sockets, now we have 3 rcds in series. The site foreman goes to the...
  15. S

    Discrimination and additional CU question

    I need to install a cu in a kitchen but wanted to make sure I got the discrimination right and hopefully also inside regs. Main CU is in basement and is dual RCD, can I use a 32amp mcb on one side of the rcd and run t&e 10mm to the new CU in kitchen and use just a main switch with additional...
  16. S

    Discrimination

    A quick question on discrimination. Now in an ideal world we'll always have a larger breaker closer to the board and work down but I'm on a job where I have a 32A feed already in place and the customer wants a new board putting in and the lighting circuit replaced. Now I'm putting in a bog...
  17. 1

    Discrimination and correct implementation of Zs

    Scenario: 3 phase DNO with 100A fuses into a control unit feeding 2x 5kVA txs with combined load of 40A. We're adding 2 more 5kVA txs, one with 14A, the other 21A. What I've come up with so far: 63A fuse consumer side will need replacing with an 80A BS 88-2 (gG) fuse (max Zs 0.57Ω)...
  18. M

    Cable size for single phase motor control panel

    Hi all, Your help would be appreciated. We are mainly domestic sparx so I havn't much experience with cable sizing for motors. On site, we need to supply a motor control panel which operates the sewage pump. There are in fact two pumps but I think they switch between periodically to prolong...
  19. S

    Urgent help with discrimination

    Hi Guys Urgently need clarification on something please. I'm currently sitting in darkness in a shop where for the last 24 hours two phases out of three on the incoming service cable have been blowing within 5 minutes of power being restored. So far I THINK I've narrowed it down to a till...
  20. C

    fuses/protective devices

    can anyone explain per-arcing i2t, arcing i2t, total let through energy. in relation to fuses/protective devices

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