Voltage drops on 120v but not on 240v?

Thread Starter

the_uglydog

Joined Aug 5, 2020
10
Hi, We have a large property located in The Philippines. Here they use a similar system to the US with two 110v legs and a neutral, no grounds. The difference is outlets and lights use the two 110 legs to make 220v and the neutral is mostly unused. Our property is like the US and has both 220v and 110v so we can have US appliances and TVs so we installed it like the US as best we could here. We use the 110v legs together for 220v but we also have 110v breakers with neutrals bound outside the panels (panels with bus bars are not available here). There are multiple sub panels with the neutral connected to the main neutral, then to the utility neutral and to a single ground location. The electricians who did the installation were supposed to run an extra wire for a separate ground but connected all the grounds to the neutral, so we have a system like the old way, no extra grounds. (the foreman didn't catch it and it tested correct at all the outlets so I didn't notice until I started a solar installation and went looking for the ground) Construction is finished and it's cost prohibitive to change it to have a separate ground.
We are having a problem with the 110v that has occurred since we connected the ground rods about 4 days ago. (a Typhoon came through at the same time with about 6" of rain and 80mph winds) When ever any appliance is turned on, the voltage drops. The flat screen TV drops the voltage from 110v to about 89v, a coffee maker drops it to about 95v, a microwave drops it to about 75v, the washing machine wont work at all. Both legs of the system have the same problem, but the 220v is not affected. One day for a few hours everything worked perfect. Sometimes the voltage in both legs is the same other times it is different, 123v in one leg and 109v in the other, sometimes the other way around. It worked OK before we added the ground and connected both halves of the system, but there was at times up to 30v showing on the neutral if checked to a ground before we started, I don't think our ground connections are the problem because all connections are tight and there are 3 ground rods connected together for the one ground and we can't find any differences in voltage on any wires at our connections. I noticed inside the box at the drop was soaked from the rain and I can see some discoloration on one of the wires. The electricians here have no idea whatsoever, I'm thinking a loose connection at the drop. It's illegal to touch the drop, even though the drop connections here are not connected correctly they are simply spliced in with electrical tape wrapped around them. (that's how the utility does it!) Your thoughts would be greatly appreciated. I'm not an "expert" but I have installed a 12kw, a 4kw and a 10kw solar systems here and rewired about 8 houses in the US myself before coming over here, so I have somewhat of an idea what I'm doing. I'm planning on hooking the 110v into my 10kw solar system, but I want to get it working as correct and safe as I can first.
 

Ramussons

Joined May 3, 2013
839
Is the Neutral link to the Transformer source still connected? Or did it fail during the typhoon?
You cannot replace a Neutral link with an earth, except where the load is negligible, and this too is NOT correct.
 

MisterBill2

Joined Jan 23, 2018
6,736
The symptoms indicate a poor or missing connection in at least one location, and since one side voltage drops while the other increases at least one poor connection is in the neutral line.
The diagnostics will be different if you have a reliable voltmeter available. If no meter is available then an inspection and tightening of the neutral and line connections, starting at the entrance, would be the choice.

So please let me know if a meter is available for checking, or not.

If a reliable meter able to see a change of one volt on the 110 volt line is available then the first step will be to measure the line to neutral voltage at the input to the distribution panel from the power meter. If the incoming voltage changes as a load in the house is switched on and off then the problem is outside. Next would come checking the voltage between one of the 110 volt sides and the different neutral connections near the main panel. A poor connection will be indicated by changing voltages as a load in the house is switched on and off. If the poor connection is in that area then this should help to find it.

Another method of locating the poor connection will require a temporary independent ground connection to use as a reference. The temporary ground will only need to be good enough to serve as a reference point for the volt meter, so it does not need to be able to carry much current.
 

BobTPH

Joined Jun 5, 2013
2,505
Agree with @rasmanson, it sounds like you have no link or a very weak link to the transformer neutral. This puts all the loads on one side in series with all the loads one the other side across 230V., and the two voltages will fluctuate with the loads.

Bob
 

geekoftheweek

Joined Oct 6, 2013
507
I'm agreeing with others here. You either have a loose neutral or a bad wire... probably got knocked loose or damaged in the storm. Hopefully it doesn't take talking to the right person at three in the morning to get someone to look at the right areas (been down this road once).
 

Tonyr1084

Joined Sep 24, 2015
4,914
Sometimes L1 (Line 1) drops, sometimes L2 drops in respects the neutral? That's the common point - the neutral.

The wires are spliced together with electrical tape? How? Twisted together? Wire nuts? Crimps? That may be how they do it there - but it doesn't sound strong.

You've wired some homes in the US, so you have "some" experience? Makes me a little concerned for those eight homes you did in the US. How do You make your splice connections?
 

MisterBill2

Joined Jan 23, 2018
6,736
It might also be a case of aluminum wire, which will always corrode eventually, and result in an inadequate connection. And aluminum wire PLUS an incorrectly attached mains connection is certain to cause problems.
My guess is that the typhoon loosened the neutral wire connection. But if you are not allowed to touch those then you will need to have the utility people fix it.
If you are able to obtain a 220 volt input transformer then you could have your own neutral and not need the utility company neutral connection. The transformer will need to have a center-tap or a 110 volt secondary. Certainly it is not a cheap solution, but it could work fairly well.
 
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Tonyr1084

Joined Sep 24, 2015
4,914
It might also be a case of aluminum wire, which will always corrode eventually, and result in an inadequate connection.
Had an aluminum grounding rod adjacent to the detached garage. It rotted and broke. Had to replace it. Had pictures of the aluminum feeder wire from the low voltage side of the transformer that absolutely burned away. I think it's on the other computer. I'll go have a look. If I still have the pic's I'll post them.
 

MrSoftware

Joined Oct 29, 2013
1,865
Try to simplify the wiring as much as possible and still reproduce the problem. Turn off all of the breakers, find the circuit nearest the panel and turn that one on, try to reproduce the problem there. The idea is you want to eliminate as much of the house wiring as possible to try to prove or disprove that the issue is outside the house. Once you have the simplest case, start trouble shooting from there. If drawing 110v power from either leg causes a voltage sag relative the neutral, but drawing from 220v by using both hots does not, then the problem is almost surely related to the neutral.
 

MisterBill2

Joined Jan 23, 2018
6,736
Because the problem is seen all through the house, it is most likely at the distribution point or before that point. So for the first check how about the breaker panel and the common point associated with it.
As soon as the meter connection between common neutral and either phase is moved toward the entrance before the bad connection the voltages should not change as loads are added and removed. So it should be better to move just one connection at a time.
One caution is that disturbing a weak connection may result in it opening completely, which will put most of the 220 volts across whatever is connected to the most lightly loaded line side. So disconnect things that could be damaged by over voltage being applied. But you will need a load to produce the difference, so switching all the breakers off will make finding the poor connection impossible.
 

MaxHeadRoom

Joined Jul 18, 2013
21,246
Hi, We have a large property located in The Philippines. Here they use a similar system to the US with two 110v legs and a neutral, no grounds. The difference is outlets and lights use the two 110 legs to make 220v and the neutral is mostly unused.
It definitely points to a high resistance in the neutral.
You need to measure the neutral as close to the service suppliers entry point to get the full picture.
I assume you inherited the USA system due to the 48yrs of US colonization of the Philippines!
Rather than the 3ph system used to obtain 1ph service as mainly used by the rest of the world.
Max.
 

nsaspook

Joined Aug 27, 2009
7,482
When I lived there we didn't use the 110 power from the utility in the house off-base because of these types of problems. The power drop was a rats nest of taped/tapped connections to a overloaded pole transformer. All 110VAC feeds were from personal isolation/step-down transformers powered from the incoming utility 220VAC feed with a separate derived system ground for proper 110VAC neutrals and ground pins on a per room external power strip.
 

nsaspook

Joined Aug 27, 2009
7,482
It definitely points to a high resistance in the neutral.
You need to measure the neutral as close to the service suppliers entry point to get the full picture.
I assume you inherited the USA system due to the 48yrs of US colonization of the Philippines!
Rather than the 3ph system used to obtain 1ph service as mainly used by the rest of the world.
Max.
It's the worst of both worlds. 220 and 110 volts on the same type sockets in houses.
 

MisterBill2

Joined Jan 23, 2018
6,736
Yes, the destroyed ALUMINUM neutral wire. Certainly it costs less, but that is only the initial cost. It is cheaper to do it right than to do it over. At least usually it is.
 

Thread Starter

the_uglydog

Joined Aug 5, 2020
10
Hi, Thanks for all the input. Yes, we do have the US based Meralco utility here. I do have good multi meters and clamp meters. I don't know what type of wire the utility uses, when they come I'll watch when they work on it. The connections are terrible at the drop. They are only twisted together and taped with electrical tape, no wire nuts, no crimps. Yes, just like the off base rat's nest of spliced, exposed wires. Funny...that's my exact words!
From the drop, all the wire for the 110v part of our house is new copper 2 years ago. All the wire from the drop to the panels is also copper new 2 years ago. We separated the system into 2 parts. On one part there is only the neutral to the utility and the power drops to 60v when the washer is turned on. The other side has a ground and a neutral to the utility and the power only drops to 88v when the microwave is turned on. When both sides are connected together either the washer or the microwave drops the voltage into the 60s. When the solar is running the 220v panels connected to it have the voltage remain stable with both legs at 120v, then when it's on utility the legs go back to uneven readings.
Today we'll check back from the drop and see where the problem starts.
All your help is greatly appreciated! the dog.............
 

nsaspook

Joined Aug 27, 2009
7,482
We also had a AVR (old relay taps version) on the 220 side to compensate for utility voltage drops and over-volts. You could guess the time of afternoon by measuring the input line voltage. During the peak dry season the AIRCON would burn out the compressor due to low voltage from the overloaded pole transformer if you didn't use a voltage regulator.
https://meijielectric.ph/avr-supplier-philippines/
 

drc_567

Joined Dec 29, 2008
870
If the 220 volt supply seems to be dependable, as mentioned previously, obtaining one or two 10 KVA, 220 to 110 transformers may be an option to consider. If a single transformer is not enough, it is possible to wire them in primary parallel, distributing the load side. A quick look at the U.S. market shows they are readily available ... Even used units.
 
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MisterBill2

Joined Jan 23, 2018
6,736
OK, and it is interesting that both sides of the line drop. That may point at something else other than a neutral problem. It might be useful at this point to have a separate ground for one side of the meter being used to check with, so that you can see what each part of the circuit is doing, without being referenced to another part. It might be that there are three poor tap connections, and since things are just twisted and taped that could be what you have. A string of poor connections may be the problem, rather than just one connection. Why wouldn't a utility company use proper cable connecting equipment?
 

shortbus

Joined Sep 30, 2009
7,853
Yes, the destroyed ALUMINUM neutral wire. Certainly it costs less, but that is only the initial cost. It is cheaper to do it right than to do it over. At least usually it is.
The local utility here only uses aluminum wire from the pole to the house. With no problems whatsoever.
 
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