Hi all Low Yat forumers,

I've got a electrical cable problem at home. After some diagnostic, i've concluded it's probably a short circuit with the "Live" and "Neutral" cable. I dont want to pull another cable from the socket to the Main DB. How to fix this issue? Tap from from another socket? = Not possible as I need lots of power for this socket (1hp aircond and 5 desktop pc)

Can I pump liquid cement into the piping and hope when it hardens it will form as an insulation for the cables laying inside?

Do suggest. Thanks.
Ykeong

It is not easy for a Live to be shorted to Neutral inside the piping, unless thare are pests that have entered into the pipings and started chewing away into the rubber insulation, which is quite abnormal too.

If there is really a short, then it must be somewhere accessible along the wirings, and you can easily reach this point and remove the short.

Otherwise, the problem could be something else, and not a L-N short along this looping. Hev you measured the L against the N with a DVM ?

1hp aircond and 5 desktop pc? Are you sure is not one of your equipemnt which given problem or properly over heat on the cable?

You may want to moved your 5 PC to other socket (Not from same loop) to see whether issues remain or not.

Also, is your problem ""short circuit" with or without equipment on it already caused ELCB jump or ? Because if indeed L/N touch, than you not even need to use the socket at all....

Are you overload your socket? Quiet high your load. And you using extension socket too?

Find the source of problem, else you risk burning the cables worse the house.

Depend your 5 pc power ratting. If one Pc use 300Watt, 5 PC use up 1500 watt, and 1HP use about 1000watt on running (bur startup is higher). You putting the socket near threshold.

ac with, 5 desktop ? sure a NO NO..

usually AC will be by itself having a direct cabling to the DB... one..

you do like that you gonna burn your cable.. do note not everybody/everyhouse is using HIGH QUALITY WIRING or gauge...

Won't be surprise, if the cable is not a continues length and its joined lol

you can test the short by leaving the AC by itself, if it runs find for a week without short and etc.. means the cable is not the issue..

NEVER OVERLOAD unless u want to claim fire insurance for your home/house

Bad idea.

Should find the cause of it.
Electricity stuff, don't play play.
It is dangerous.
Somemore 5 desktop + air-cond cost is way expensive than finding the root cause of it.
You are putting 5 desktop at risk.

How come you conclude short circuit between L&N?
If there is short-circuit, your ELCB will trip straight away once you open the ELCB switch.

A normal socket/single 13A supply supply, may not enough for 5 desktop + 1 hp aircond.

1 hp = 0.75KW = 3-4 A
A desktop normal power supply = 400W x 5 = 2KW, = near 9 A
Total = 13-14 A.
This is dangerous, you are pushing the top limit of the cable/socket rated ability

If L/N touch.. it is not the ELCB that trip.. is the MCCB that will trip and you will see a spark/burning sign on your cable.

frm here, i can see that it is most possible that is overloading and your MCB is tripping but not the ELCB..

assume that your 1st point of the circuit is to AC.. then you can loop the 5 pc from another socket.

1. Split unit Aircond (1hp) rating at 4.1 Amps
2. 5x PC (Rating of 1.5 Amp each) = 7.5 Amps

Total = 11.6 Amps. If I round it off to 15 Amps it would still be within the rating of 2.5mm gauged cables (rated at 18amps).

ELCB and MCB trip. Everytime I tries to turn the MCB on, ELCB will trip and there's (small sparks) within that MCB.

With MCB off:
- Test with multimeter (on connectivity) with L and N, it beeps.
- Disconnected every devices.
- Remove cable from socket (exposed) but not touching each other.

I'm pretty sure it's a short circuit on the cable. Question now, how can I do a quick fix on this problem without:
1. Hacking the entire wall to remove the cable
2. tap from other socket because it's either too far or not safe (due to load).

What are my choices?
1. Pull 1 new cable from DB to room
2. ???

Any advise guys?

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Added on October 25, 2011, 1:39 pmI'm most certain have to hack oledi. Here are my choices:
1. Buy 1x 40amps 3 Core Submersible Cable (farking expensive), and pull it from DB to room. Loop this cable to another 15A socket for Aircond.

2. Buy 2x 18amps 3 Core PVC cable. Pull both from DB to room. 1 for PCs and the other for Aircond.

Environment:
- to hack outdoor wall which is exposed to sun, heat and rain.
- to conceal the cable either by itself or in PVC within the hacked wall.

Problems:
- Hacking outdoor wall and plastering it back later may cause water seepage into the inner walls.
- May cut other cables along the way?
- hacking indoor not possible as it's either way too tedios or will affect too many items / concealed cables etc.

Questions:
1. Use submersible 3 Core cable or PVC 3 Core enclosed in PVC Conduit?
2. Use 1x 40amp cable or 2x 18amp cable?
3. Can I trace where the short is? any device that can tell you that?

Thanks all.
Ykeong

This post has been edited by wyekeong: Oct 25 2011, 01:39 PM

seldom see people used 3 core cable.. they usually pull each L,N,E separately

which is better you seem knowledgeable

wyekeong: your cable is in a conduit or flexible hose? if in a conduit.. pull it out, cut the short circuited area, join them back using cable link, then lay it back ..

If a cable been conceal and never have problem, what will cause the cable short? Due to external factor? Or could it be the socket screw losing or perhaps try change another socket (maybe just an stupid idea)?

+1 on 2. Buy 2x 18amps 3 Core PVC cable. Pull both from DB to room. 1 for PCs and the other for Aircond.

My water heater at master bedroom bathroom give me d similar pro also, it will make d main switch Elcb trip even when it is not switch on, previously I have a water dripping problem from a valve on top of the water heater, could this cause by the water dripping make d wire short or the water heater short?

I got a wireman check on it, but ut seem that he still can't identify the causes of trip, and when he join back all d wire the water heater work as normal , but after a while the trip happen again, any idea?

If without the load, empty socket or wire takeout from the socket, the mcb and the elcb stil trip? With the above method, takeout the wire from the mcb and test with multimeter to N, does it beep?

If this 2 method show trip and beep, than the wire is short circuit somewhere. There is no other method to know where the wire short if didn't takeout the whole wire.

Use separate wire and mcb for each aircon and pc. If you make a new wiring. If you lazy hacking, than just use the Cable trunking.

If you want to run the cable outside but worry hack to another cable, use a device call something like volt stick. It sense the cable magnetic field and give out light and sound. I use it before on checking conceal wire.

Thanks to all for your ideas. I've decided to go with the following:
1. 1x 10mm submersible cable (40amps) from DB to Room
2. Hack outdoor 1" to fit cable in 1/2" pvc conduit (not flexible)
3. To loop 1x 13Amps to 1x 15Amps plug.
4. To put in 1x 1000VA AVR on 13Amps plug point and extend out extensions to all pcs and devices.
5. To use "water proof cement" to conceal outdoor hacking

To some of your questions.
1. 3 cables LNE are used because it's easy for the electrician to loop and it's cheap also (depending on brand).
2. 3 Core 18 Amps cable are expensive. They are difficult for lighthing loop.
3. L and N short how to pull them out? Cables are concealed. I dont even know if those electrician uses the same conduit to run other cables to other location. If I tried pulling them out, I may even damage the other cables in the conduit. Besides, it's twist and turn over 20 meters.
4. I was hoping someone can tell me how to pin point the short within a concealed wall. A network cable scanner can tell you the short happen at how many meters. Wonder if they have such scanners for electrical cables . Then I dont have to hack 20m but only hack 1 place .
5. Yes, I bought the electrical and metal scanner. It will only work to about 1" depth. Insulated cables are not traceable. Hence if power cables are concealed within 1" PVC and under 1" of cement ... it's difficult to trace.

I think this should work. After much consultation, I think this is what happened. When the developer electrician pull those cables, they tend to over stretch the pvc sleeves that coat the cable hence making certain part of the cable having thin PVC. When I run the aircond + 5 pc together plus heated bricks (due to sunlight) increases the heat within the PVC conduit to more than 70 / 90 degrees celcius. Because the pvc sleeves are thin on those areas, and the load is high (15Amps), plus a sudden surge of electricity due to lightning ... it could have melted both the L and N PVC sleeves. Hence the "touch".

Thanks all.
YKeong

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Added on October 26, 2011, 5:26 pmYes, most likely. Water conducts electricity. If your cable short circuit many times it's also likely that more than 1 part of that cable that connects your water heater is already defective. My friend's water heater cable actually catch fire when he was bathing!.

You can try to remove the cables that connect to the heater, tape it off each of the cable and turn the power on. Leave it on for a few days. If your ELCB doesnt trip, that means your water heater is problematic. Get it replace before it burn your house down .

This post has been edited by wyekeong: Oct 26 2011, 05:26 PM

TS, I might be able to give u better solution. Before that, I'm suspecting that u found the wrong fault.

- proper tools to use is insulation tester instead of DVM.
- Incoming MCB or Outgoing MCB trip?
- Did u manage to locate all the SSO looping from the same shorted circuit?
- Is the SSO the 1st point or last point or intermediate point?
- Any conductivity between L/N with E?
- Using GI or uPVC conduit?

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Added on October 27, 2011, 12:02 amHow sure are you the ELCB trip is due to fault from that water heater since it will trip even when its not on? ELCB tripping on and off is a little difficult to troubleshoot.

If you are sure about it, get the wireman to do insulation test on that cable.
Other possibilities is the water heater giving problem. Try plug in other appliances to the socket, possibly, suggest to plug in 2 Nos 100W incandescent bulb connected in series to the socket to see if it lights up or trip.
Else, neutral cable returned to the wrong ELCB. This happen if you have 2 Nos. of ELCB in the whole house, either in the same DB or inside 2 DB at ground floor and 1st floor.
Else, ELCB having problem


This post has been edited by pky: Oct 27 2011, 12:02 AM

really have no idea what is going on now, but the wireman did suggest the same as yours, disconnect the cable and see if it trip, but he is too busy for a small work like this, have to wait n follow his schedule, aih..

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Added on October 31, 2011, 9:31 amactually i also confuse about this, cause the water heater seem working fine when the wireman connect back all the wire, it only trip after several hours but that is when the heater is off. would suggest what u mentioned to the wireman see what is he comment. thanks lot

This post has been edited by Apscen: Oct 31 2011, 09:31 AM

Is the heater wire only use by the heater or have other device connected alone the way? whihc may want the electrcian to check too

This is not normal.
It shouldn't trip, whether the heater is on or off.