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What is the maximum insulation resistance reading on a ring main circuit?
Wiki User
∙ 14y ago
Insulation resistance is measuring the integrity of a conductor's insulation, therefore there is no upper limit as such. Most insulation resistance testers will indicate either >200 (Megohms) or >999 (Megohms) if they reach their maximum measuring capability. What you should be concerned with is the MINIMUM reading permissible: the current edition of BS7671 (17th Edition IEE Wiring Regs) specifies a minimum value of 1 Megohm (1 million ohms) as 'acceptable', but anything lower than 2 Megohms will require further investigation. Some electrical contractors would investigate much higher readings, especially if comparing readings with other circuits that have been tested at the same time, and which have given very high readings.
Wiki User
∙ 14y ago
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What test would identify a short circuit in a lighting circuit?
earth continuity insulation resistance polarity
When a multimeter is set to measure resistance what reading would you expect when the probes aren't touching?
If the test leads are not in contact with anything, the needle or pointer of an analog meter will be resting at the left most position. This is represents an infinite amount of resistance, or an "open circuit"; it is also safe to say there is the no continuity, or path between the black and red probes.
Why must power be turned off when measuring the resistance of a circuit?
If an external Voltage is applied to a multimeter while the multimeter`s function switch is in the Ohm meter position then the Ohmmeter is apt to be destroyed or disabled. Therefore the simplest answer is that the power must be turned off in order to avoid damage to the Ohm meter and possibly to yourself caused by Voltages present in the circuit while the power is own. Another reason of course is because a valid Ohm reading can not be obtained while Voltages are present across the resistance that is being measured because the Ohmmeter itself applies a Voltage across the resistance and then a sampling of the current through the unknown resistance is used by the Ohmmeter`s circuitry to cause a calibrated deflection of the Ohmmeter and thus display on the meter`s dial the Ohmic value of the unknown resistance. For the same reasons as above it is also a good practice to discharge all the capacitors in the circuit after the power is turned off and before any in circuit resistance measurements are made.
How does read-out integrated circuit works?
Read out integrated circuit refers to integrated circuit specifically used for reading detectors of a particular type. These are used in detectors where the sensitivity is very low and using a discrete circuit may not be useful as noise may be large enough to cover up whole signal.
What part of the ohms scale of a meter are the most accurate resistance measurements made?
It really depends on what you are trying to get the resistance of. A piece of copper wire 30 feet long will only have a resistance of few ohms. A person can have a resistance of several million ohms. Making sure that your meter's leads are in good contact with whatever you are measuring is the best way to get an accurate reading.
What is the maximum insulation resistance reading on a 800A busbar?
infinite
If you are using a multimeter as an ohmmeter and you get a reading of maximum resistance what does that tell you about the circuit you are measuring?
Did you mean "maximum RESISTANCE" or "maximum VALUE"? If the former, then, you have a ZERO reading, meaning there is high resistance, and no electrical connectivity. If the latter, you have a ONE (or 100%) reading, meaning there is NO resistance, or absolute electrical connectivity. As an analogy, if you turn on a plugged-in, working, lamp, then it has NO resistance, such that power flows easily through the cord; if it didn't turn on, then there IS resistance, such that no power flows, possibly due to broken wire, bad switch, burned-out bulb, or blown fuse.
What test would identify a short circuit in a lighting circuit?
earth continuity insulation resistance polarity
Why remove resister from circuit to measure resistance?
a meter uses its own supply to measure resistance. you dont have to remove the resistor from the circuit but you must isolate it from the circuit supply to get an accurate reading.
What should be the insulation resistance in a electrical circuit?
As we know thath insulators are the materials which are mainly use to insulate any conducting body from the LIVE supply whether 3Ph or single phase, so the reristence of such an insulator should be infinity as it should be provide maximum resistance to the flow of current through it.
Why must do the insulation testing in circuit?
Insulation resistance testing involves applying a voltage across a dielectric, and measuring the resulting current and resistance. However, in order to get a proper reading, any electrical charge still within the system needs to be taken out, so as not to mess with the readings.
Why does the voltage reading of 110 circuit is less than expected?
A load or a resistance
What is resistance reading?
A measurement of opposition to electric current flow in a component or circuit.
How can an ammeter loading effect the circuit under test?
Since internal resistance of the ameter will increases the resistance of the circuit. Thus decreasing the current giving an errorenous reading.
Does an Ohmeter that has an infinite reading indicates an open circuit?
Yes, or a circuit with a resistance higher than the capability of the meter, which would be unusual.
Why insulation meter of LT panel shows low insulation reading below 500k ohm?
The only reason this would show is that the circuit has leakage to ground. This is still well above tripping current but the potential is there to advance into a short circuit.
Does a Resistor have a different resistance when connected to a power source vs if the resistance is tested when the resistor is out of circuit?
In the circuit it is connected to other devices with their own properties that can influence your reading. Out of circuit you just measure the resistor. It has the same value both ways.
