0
by design MICC has a very insulation high resistance. This is measured in Mega Ohms between conductors and between conductors to cable sheath. This high insulation resistance is provided by a highly compressed mineral keeping bare copper conductors apart all within a copper tube called the sheath. Each end of the cable is terminated on site by the engineer to the appropriate length. The termination provides a pot attached the the end of the cable to prevent the ingress of moisture and also a way or providing insulation to the bare conductors. The mineral insulating material in the MICC is quite absorbent so if any moisture is able to get into the cable it will reduce the insulation value of the mineral. Any breach in the integrity of the sheath will allow the cable to breath in moisture and will result in a drop in the insulation value of the cable. The breach can be caused by damage to the sheath by a sharp impact or by age where corrosion to the copper sheath results in a hole. Poorly fitted or damaged terminations can also cause a similar breach and consequent drop in insulation value.
As a temporary measure if the damaged section of cable is identified. Isolating the cable from the power supply and providing gentle heat to the outside of the cable with a hand held hair dryer can often improve the insulation resistance value by gently driving out the moisture.
It will of course be necessary to replace the damaged section of cable or re assemble the terminations as soon as possible.
Wiki User
∙ 12y ago
Add your answer:
Earn +20 pts
Using blavier test to check for cable faults?
This is use to locate the ground fault of a single cable. This test is performed with the aid of a low voltage supply with an ammeter or voltmeter. In this test the resistance between one end of the cable C1 and the earth is first measured with the other end, C2 isolated to earth and then with the C2 earthed. Let the two readings be represented by R1 and R2 rep! If r1 and r2 are the conductor resistance of the length of cable at C2 to fault and at C1 to fault rep!, and "r" is the resistance of the fault to earth
Items that use low resistance wire?
Ni chrome is a low resistance wire used in heaters and toasters.
What are the disadvantages of low carbon steel?
Abrasion resistance is low.
Is it desirable for a battery to have a high internal resistance?
No, it is desirable for a battery to have a low internal resistance.
Why is my resistance so low?
She said that after I get over this most recent bout of illness, she is going to send me for blood tests to see why my resistance is so low.
What are the faults in the cable?
Cable faults are normally categorised as (a) conductor-to-earth (ground) faults, (b) conductor-to-conductor faults, and (c) conductor-to-conductor-to earth (ground) faults. In addition to that, we can categorise them by whether they are 'high-resistance' or 'low-resistance' faults.
What causes low voltage to the transmission selonoid?
Cables aren't perfect conductors, they have a bit of resistance. This resistance cacuse a certain voltage drop. But the drop isn't proportional to the voltage running through the cable, so at lower voltages the proportion lost to internal resistance in the cable will be bigger than at higher voltages.
Does plastic have low resistance?
yes, it does have low resistance
Is graphite a high resistance or low resistance of electricity?
Graphite is low resistance of electricity...
What is an LT cable?
An LT cable is a low tension (or low voltage) cable.
Which has the thickest filament - a high-resistance or a low-resistance bulb?
A low resistance bulb has a thicker filament.
Does gold have a high or low resistance?
Gold has a low resistance, which means it is a good conductor of electricity. This property makes it useful in various electrical applications where low resistance is needed for efficient conduction of electricity.
Good conductors have a high resistance or low?
Good conductors have low resistance
If voltage and current are proportional why do they increase voltage in powerlines in order to decrease current?
Low current will equal low power losses due to the resistance of the cable. I squared R. (I is transmission current and R is resistance/Metre of cable) by increasing the voltage for the same amount of power the current decreases. Power transmission will take that advantage to transfer less current for the same amount of power.
Will increasing the cable size improve the performance quality of home theater speakers?
Probably not. There are several factors that can affect the performance of speakers including the signal itself, the amplifier, the cables and the room in which the speakers are used. There is a school of thought that says certain types of cable can have a noticeable effect on the sound quality even though test equipment monitoring the same tests is unable to record a difference. These people may be right or may not but for this answer we will ignore the un-measurable subtleties of types of cable. In a typical home set up, speaker cables are likely to be under 10 feet long. The resistance of the cable will be up to around 0.5 ohms if the cable is a thin figure of eight style. A typical speaker is around 8 ohms so the cable resistance is just 1/16th of the total resistance. Increasing the size of the cable, even so that it has no effective resistance will affect the total resistance by only 6%. Resistance is important because it affects the amount of power being delivered to the speakers. Using thin cable will demand that the volume of the amplifier is adjusted upwards by up to 6%. Speaker resistance isn't quite as simple as a fixed resistance. Typically, the resistance is far lower at low frequencies than high frequencies. An 8 ohm speaker may actually be as low as 3 ohms at 100 hertz (low frequency rumble). Because the cable resistance is more significant compared to the speaker resistance at these low frequencies, it is possible that there will be some small losses of low frequency. The two ways to overcome it are to increase the wire diameter or turn up the low frequency equalization just a touch. As a sensible guide, try to use at least 0.5mm or 20AWG cable for a 10 foot run. The total resistance will be in the region of 0.2 ohms and make sure the cable is clean and firmly attached to the terminals. Be aware that moving the speakers even a small distance in the room can have more effect on the sound than the cable. Speakers close to a corner of a room, for example, will increase their low frequency output significantly (by a factor or 2 or more in some cases). Moving a speaker closer to soft, absorbent furniture can reduce the high frequency output by 50% or more. While cables are important, speaker position can play a far bigger role in the final quality.
What wire connection better high or low resistance?
Usually low resistance is better.
Using blavier test to check for cable faults?
This is use to locate the ground fault of a single cable. This test is performed with the aid of a low voltage supply with an ammeter or voltmeter. In this test the resistance between one end of the cable C1 and the earth is first measured with the other end, C2 isolated to earth and then with the C2 earthed. Let the two readings be represented by R1 and R2 rep! If r1 and r2 are the conductor resistance of the length of cable at C2 to fault and at C1 to fault rep!, and "r" is the resistance of the fault to earth
