Replace Transformer or Keep Looking

[cworld29]

New member. I have been coming reading for a few months but decided this might be an interesting discussion.

I am troubleshooting a noticeable flicker problem in a residence. 2 1500 sf houses on 1 5kva xfrmr served by #2 triplex. One house is about 100' away the other is down line another 300'. Seems like a voltage drop issue to me but others keep saying loose neutral.

Share your rules of thumb for service drops please.

 

[ptonsparky]

Loose neutrals will cause some lights to brighten while others dim. Connect two volt meters at the service panel checking L1 to Neutral and L2 to neutral. Turn appliances on/off and watch the voltage swings as you do so. Electronics have a tendency to let the smoke out with bad neutrals so using a couple small space heaters may be better. Voltage will go high on one meter and low on the other.

 

[ptonsparky]

A 5 is terribly small for two homes, even one, IMO.

 

[Ravenvalor]

Flickering problems could be loose hot also. If both the residences are flickering then the problem is at the transformer. If only one residence is flickering then look for corrosion in side of a main lug. Sometimes you cannot see corrosion on a large lug until you loosen the lugbolt and pull the conductor out of the lug.

 

[beanland]

5kVA

5kVA

Flicker can be caused by a loose connection (hot or neutral) which will be evident as changes in voltage even when current is the same. But high impedance will be caused by all of the devices in series: utility primary, utility transformer, service drop. If you calculate the impedance of each, I think you will find that most of the impedance is in the 5kVA transformer. If both homes have gas heat, then 10-15kVA for normal power is reasonable. If both houses have A/C, then 25-37.5kVA may be needed. #2 may have plenty of ampacity when out in the free air, but for a 200A service, 2/0 would be more appropriate.

 

[jumper]

I gotta say that a 5kVA tranny serving two dwellings is a bit abnormal, even by POCO standards.

 

[cworld29]

Thanks,

Standard procedure is usually deny and counter accuse. lugs have been checked in the meter base, the beast has been applied, nothing has been out of the ordinary. I think it is just too small a pot and too long a service of too small a wire. I hate to tell the consumer to start tightening wire nuts in a situation like this but the house that is connected closer to the pole does not report any noticeable flicker.