theory

  1. P

    Reason for usual HW shutoff valve location

    In a conventional system, the standard arrangement is to have a gate valve on the (typically 28mm) cold feed pipe from cistern to cylinder. Out of curiosity, I was wondering why you won't find it on the hw pipe (typically 22mm) going out of the cylinder instead. Of course, positioned after the...
  2. eveares

    How do you calculate the complex power phase angle (φ) for reactive power calculations?

    I know you can find reactive power out from the alternative formula below, but using the formula "P(W) = V(V) × I(A) × cos φ", how do you obtain the complex power phase angle (φ) from knowing the Voltage, Power and Current? Alternative formula: Reactive Power=√ (Apparent Power²– True power²)...
  3. V

    SL, N and L any good UK Electrical theory book?

    Hi, this is my first post and I admit, I have not read the rules yet, so please go easy on me. I am not a qualified electrician but come from a science background so I know the basics quite well. Recently, I replaced an old PIR Bulk Head with a new PIR Bulk Head. While replacing the light, I...
  4. eveares

    Diversity of two single ovens?

    So was doing a little paper excessive to keep by brain active. If you had: A) A single oven rated 3.5Kw (i.e. Steam oven) and B) A second single oven rated at 3.0Kw (i.e. Microwave combi oven) That would give you a current rating of 11.56A for the first oven and 10.91A for the second oven...
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