Saturday, November 18, 2017

FAQ

  • Do I need to install Surge Protection for My Home?
  • Is Aluminum Wiring Safe?
  • How GFCI works and where they must be installed?
  • Is Knob and Tube wiring safe?
  • why my electrical wiring need to have grounding system?
  • What is ARC and where I need to use ARC Fault breakers?
  • I can hear a buzzing noise from my electrical panel, is that normal?
  • Can I install a separate electrical meter for my basement unit?
  • How far the switches must be from the bathtub or shower stall in bathrooms?
  • How can I find out what size of wire I must run and what type of outlet I must install for a particular load?
  • How can I find out if a light fixture or an electrical product is safe to be installed in my house or building?
  • How 3 way and 4 way switches are wired?
  • Is it legal to burry current carrying wires underground? If so, how deep they should be burried?
  • Some of the pot lights in my kitchen which was renovated recently occasionaly go off and come back on after a while, why?
  • Q 15?
  • Q 16?
  • Q 17?
  • Q 18?
  • Q 19?
  • Answers:

       

    1. Do i need to install Surge Protection for My Home?
    2. You may not realize it, but your stereo system, home computer, television, VCR, microwave oven — anything with internal
      electronic circuits — is under attack every day. The attacks are silent, but destructive. Surge protection or surge suppressor
      blocks or shortens to ground voltages above safe threshold.

    3. Is Aluminum Wiring Safe?
    4. Primarily in mid 1960s to late 1970s, many electrical contractors used aluminum wire because of high copper price. Since then a number of electrical fires have been attributed to aluminum wiring.
      Many building codes have been rewritten to not allow the use of aluminum wire for branch circuit wiring in houses. Two problems associated with aluminum are:

      a) When higher current flows through
      aluminum wire, it expands and when less or no current flows through it , it contracts. after many
      occurrences of expansions and contractions very slowly, but progressively connections become a bit
      loose and causes small arc and heat build up which gradually deteriorates insulation and
      eventually causes short circuit.

      b) When aluminum comes to contact with other metals such as copper, it corrodes and causes the resistance of connection to go up and that in turn causes heat build up, deterioration of insulation
      and short circuit.

      If you notice any of the symptoms below, most likely you have issues with aluminum wiring:

      • Intermittent flickering of lights that eventually will turn into lights going out completely
      • Unusual static on radio or TV
      • Warm cover plates
      • Strange odour of plastic burning in some areas
      • Circuit breaker tripping for no apparent reason

      Remedy:

      Best solution is the most expensive solution, replace your aluminum wiring with copper. You can keep aluminum wiring and drastically reduce the risk by doing the following:

      1. Inspect your aluminum wiring (all devices and boxes) and look for and repair darkened connections, melted insulations and baked fixtures.
      2. Replace all devices (switches and receptacles) with CI/ALR rated devices.
        Don’t use push in terminals on the devices. Turn wires at least 3/4 way around and under screws in clockwise direction.
        Alternatively, copper rated devices can be used by using a short piece of copper wire pigtailed into ends of aluminum wire. CSA rated twist on marrete must be used and anti oxidant compound (such as NOlox)
        must be applied.

    5. How GFCI works and where they must be installed?
      GFCI (Ground Fault Circuit Interrupter) prevents
      electrocution by shutting down the circuit before you get
      electrocuted. You can install a GFCI breaker to protect the whole circuit or install a GFCI
      protected receptacle on a circuit protected by regular breaker.

      GFCI is constantly measuring and comparing current flowing through the hot and returning through neutral wire and as soon as current flowing in the neutral
      is lower, even by slight amount, that indicates leakage to ground and shuts down power in a fraction of a second to prevent
      electrocution. Whirlpools and bathtubs (indoor or outdoors) need to be protected by GFCI
      breakers. Also outlets in the bathroom, close to kitchen sink, outdoor and washing machine need to be protected by GFCI.

    6. Is knob and Tube wiring safe ?
      Knob and Tube wiring was standard method of wiring in 1880-1930s. in this method of wiring porcelain knobs support the wires running along joists and
      porcelain tubes provides for separation from wood when wires run through holes made in the joists.

      Currently many insurance companies will not issue new homeowner policies unless all knob and tube wirings are removed. Others require a certificate stating that Knob and Tube wiring is in safe condition.

      Here are some of the problems associated with Knob and Tube wiring:

      1. No Grounding
      2. Since it was designed for usage before 1940s, Knob and Tube wiring lacks the ampacity required by loads in modern houses
      3. It is susceptible to abuse by homeowner who use a larger size fuse to avoid repeated fuse blowing and therefore causing overloading and overheating
        wires and therefore damaging the insulation which may cause short circuit and fire
    7. Why my electrical wiring need to have grounding system?
      Grounding makes your wiring system much safer. In an ungrounded system, if for any reason hot wire come in contact contact with metal frame of the appliance
      or fixture makes it live and as soon as you touch it, your body will make a perfect path for electricity to be discharged to ground. In a grounded system as soon as
      hot wire contacts the frame of appliance, a large amount of current flows though the ground wire and causes the breaker to trip and shut down the power. This tells
      you that something is wrong and you need to check your wiring.
      Also surge protectors wont work as well on ungrounded wiring.
    8. What is Arc and where I need to use Arc Fault breakers?
      Electricity can be discharged unintentionally as a result of an ARC and not only its wasteful, it might also cause fire. Arc can be caused by damaged or worn insulation,
      an object pressing the electrical cord, screws and nails driven into the wire or staple is hammered in too deep on the wire.
      Currently Arc Fault breakers must be used for bedroom receptacles in new construction and in old construction only if new wire is run to feed the bedroom outlets.
      Gradually
      the code will change to require all wiring to be protected by Arc Fault breakers.
    9. I can hear a buzzing noise from my electrical panel, is that normal?
      Panels should not make any noise. The buzzing noise is likely because one or more than one breaker is not making a good contact with the panel busbar. The connection point
      will eventually burn and that space can not be reused for replacement breaker. You should have your panel inspected by an electrician as soon as possible.
    10. Can I install a separate electrical meter for my basement unit?
      In city of Toronto, a single family home is allowed to have one electrical meter only. If your property is a multi family home and classified so by the city of Toronto, you
      can install extra meter(s) . To do that you must provide for Toronto hydro a letter called “Permitted use letter” . This letter can be obtained from the city hall only if
      your property is approved for multi family residence.
    11. How far the switches must be from the bathtub or shower stall in bathrooms?
      Switch(es) in bathrooms must be installed at least mm or 3.5 linear feet away from bath tub or shower stall, unless they are protected by GFCI breaker or outlet.
    12. How can I find out what size of wire I must run and what type of outlet I must install for a particular load?
      Tables 1, 2, 3 and 4 of Ontario Electrical code indicate maximum allowable ampacities for different types and sizes of conductors. For outlet configuration refer to diagram 1 and 2 which show CSA configuration for locking and
      non locking receptacles.
    13. How can I find out if a light fixture or an electrical product is safe to be installed in my house or building?
      If a light fixture or an electrical product has CSA (Canadian Standard Association) or UL (Underwriters
      Laboratory) label, then it is safe to be installed otherwise its unsafe and illegal to be installed in Canada.
    14. How 3 way and 4 way switches are wired?
      If you would like to switch one or a group of light from 2 locations, then you need to wire up two 3 way switch as is shown in diagram “A” .

      To better understand 3 way wiring, follow current path in this diagram and decide if in this position light is on or off.
      If you decided that light is on, then you are right. Diagram “B” shows the switch positions, if switch 2 is flipped. Follow the current path again to understand the circuit better.

      When installing switches, note that traveller wires must be connected to two screws usually in brass colour and the other wire (power or return wire to light) is connected to
      the third screw which is usually in black or copper colour. For switching the light from 3 location (or more) just add one (or more) four way switch as shown in diagram “C”.

      Diagram “D” shows how the contacts in the four way switch changes when is is flipped.

    15. Is it legal to burry current carrying wires underground? If so, how deep they should be burried?
      It is, provided that conductor insulation is rated for
      burial or if they are in proper type of conduit, (i.e. PVC Conduit) . How deep they should be
      buried, depends on few factors
      like what the voltage is, if they are buried in vehicular or non vehicular area and if conductors have metal armour. table 53 of Ontario Electrical code shows the
      burial dept in every situation.

      Example: For a 15 A wire if it is NMWU type it can be
      buried directly 600 mm or deep and if it is in a PVC conduit, 450 mm deep.

    16. Some of the pot lights in my kitchen which was renovated recently occasionaly go off and come back on after a while, why?
      There can be number of reasons for this problem. a) There is a thermal sensor safety switch installed in every potlight. If this sensor is not working properly (i.e.
      shots down the power at lower temperature than it is supposed to , which is the case in some low quality pot lights) you will experience this problem. b) It might be
      that the thermal switch is working fine but there is an unusual heat buildup in the potlight and this switch is only doing what it meant to do. If Ceiling is insulated
      and non IC pot lights are used, you are likely to experience this problem as well as more frequent bulb burning.

    17. question15?
      answer15
    18. q16?
      answer16
    19. q17?
      answer17.
    20. q18?
      answer18.