What may cause this ?

[Dylboy]

Hello

Was at a client last week and when his house uses a large load, i.e kettle or geyser or microwave then he gets severe volt drop.

So 230V with no load then any appliance then 113V to even 7 volts I got once.

He did get council out and they say there is some issue and now made his house all on one phase.

He is still running on generator though.

But what would or possible causes of this ?

Did the the cable get like pinched or break a bit to reduce the cross sectional area therefore large loads makes a volt drop ?

What else could it be ?

Had it a few months back at another client and then council came and fixed something but they had it even if the neighbours pulled power they had the drop of volts and when everyone left for work then the house was back at 230V. I have no idea what they fixed but would like to understand



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[GCE]

Will be a loose connection on the pillar box, overhead line or fuse holder in the sub station .
Could even be a joint underground that is loose or burning back.

[Dylboy]

The loose connection causing a reduced cross sectional area basically?

I don't yet have the loop testing equipment so I did not test that but I figure a PFCC or PSCC test may come back with a high resistance on one of them.

If I come across it again will do those tests and see the reading, one should be high then.

Thank you again GCE!

If you drink you deserve a fine whisky or if you don't an A grade fillet hahah.

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[Isetech]

These type of faults generally dont just happen, it could take a couple of weeks or even months, I would normally use the thermal imaging camera and check the overhead for loose connections.

The first question I ask the customer, have the lights been flickering? Even a slight flicker on the lights are a good warning sign of things to come.

Another issue which is a massive time saver for customer who have rows and rows of 5 ft fittings. I scan the rows of fittings and make a note on the floor plan of any fittings with higher temperatures. This is a real game changer for fault finding, if you have done shop lighting maintenance, you will know the frustration of trying to identify that one blown ballast, when the mcb trips, its always the last one you check, now we just go in and open the fittings with higher than normal temperatures and bingo 9 out of 10 it is the problem ballast

[Isetech]

The loose connection causing a reduced cross sectional area basically?

I don't yet have the loop testing equipment so I did not test that but I figure a PFCC or PSCC test may come back with a high resistance on one of them.

Tapatalk

3 pieces of equipment I never leave home without, the fluke multi function tester, the fluke thermal camera and the kyritsu ( one of the few test instruments which are not fluke, but very happy with the quality) mA clamp meter.

A bad connection is normally a build up of carbon on the terminal, either from the connection being over tightened or never torqued or vibrated loose.

It blows my mind that I get reports from thermographers with complaints about "hot" spots on wires that dont show any evidence of discolouring or carbo build up and yet I find issues in panels were the wire insulation is already burnt black and yet nothing in the report. That is why I dont believe people without an electrical back ground should be doing thermal inspections on electrical panels.

[Isetech]

Another free tip: IF you find a circuit breaker getting warm or think you might have a loose connection and you think you have a bad connection in a circuit breaker, take your accurate multi meter and measure the voltage at the top (line) and the bottom (load) the reading should normally read about 10 - 60 mV, if it is higher, like 350 mV, you might need to replace the breaker. I find it is best to check all the breakers and get a general reading and use that figue to gauge the ones which might seem too high.

[Derlyn]

Here in our valley the stubby's are not locked. Actually there's quite a large percentage of them that are open without doors.

Should there be a serious volt drop on an installation, I just check the voltage in the stubby on the pavement. If low ...... Municipal problem and that's where the fight starts.
It can take anything from 3 days to 3 years to have it sorted and I ain't exaggerating.

[Isetech]

Here in our valley the stubby's are not locked. Actually there's quite a large percentage of them that are open without doors.

Should there be a serious volt drop on an installation, I just check the voltage in the stubby on the pavement. If low ...... Municipal problem and that's where the fight starts.
It can take anything from 3 days to 3 years to have it sorted and I ain't exaggerating.

I must say, our electricity department has improved their service to a point that it has been a pleasure dealing with them. I have reported high loop impedance reading, within 48 hours the customer has received a message to inform them that the fault has been lodged and they have sorted it out within 48 hours.

I have only had one customer complaint which took 3 months to sort out, they botched the repair and after sending another complaint, a different team was sent to sort out, they ran new wires and sorted out the problem.

I find it depends on the area you live, if you live at the top of the hill in a "nice" area, you get better service, as you go down the hill, so the services goes to shyte. I have moved down the hill, we dont even have a pavement for pedestrians to walk on, and our roads still look like Russia has been bombing our suburb since the floods.

[Dylboy]

Thanks for the replies and those tips as well!! The CB test on Mv is interesting and then the thermal imager as well!

I am yet to get those pieces of equipment but itching to get them!

The recent one with this Volt drop has has the municipal people out and it's been more than 6 weeks now.

Problem is I feel is that it's a ground fed via kiosk across main road.... Would have to dig up up and that will take a massive amount of planning as it's literally Main Road in Randburg haha.

But again thanks all for the replies and solidifying my ideas as well as teaching me some great things !

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