Ground wire on kitchen sink

[carluva]

One for the techs in here.
3 phase system, red, yellow and blue wires.
The main breaker supplies 2 3 pole breakers for isolators, one for air handler and one for condenser.
Condenser has a double pole contactor supplying split phase induction type fan motor and three phase compressor, blue line hooked up direct with a lug, red and yellow on line side of contactor, red and yellow on load side of the contactor.
Fan works with yellow wire disconnected from load side of the contactor, contactor coil not energised, not closed.
Works only when condensor isolator is turned on.
Leme hear allyuh...

Send a sketch. Or better yet send the actual schematic. From what you described this may not be normal but a sketch is the best way to help you out.

[nervewrecker]

I will video it.

Having a hard time understanding how a fan coming on with no power to it (contactor open) and one line disconnected.

I'm getting continuity to ground on the yellow phase with the isolator on though.

Have to check the load cable from the panel breaker to the isolator to see if that damaged and getting continuity to ground there. I made a mistake and checked to ground on the line side of the contactor and the yellow phase read continuity.

will update on details tomorrow, wanna sleep.

Got shocked with the red phase on the load side of the contactor and dismissed it as the capacitor from the fan.
Got shocked again so I assume the contactor closed, took off the cover and it was open. Checked continuity between line and load on each pole, none. Checked to ground (both sides) yellow reads continuity on line side. Thats how I checked continuity by mistake while live.
Got shocked with the signal line for the contactor coil, one side reads 54 V to ground. Air handler off so no signal / voltage should be there.

[nervewrecker]

Blue phase took some heat at one point, insulation burned off.

Another system, isolator burned up badly. Lug welded to ground from arcing.

[hong kong phooey]

One for the techs in here.
3 phase system, red, yellow and blue wires.
The main breaker supplies 2 3 pole breakers for isolators, one for air handler and one for condenser.
Condenser has a double pole contactor supplying split phase induction type fan motor and three phase compressor, blue line hooked up direct with a lug, red and yellow on line side of contactor, red and yellow on load side of the contactor.
Fan works with yellow wire disconnected from load side of the contactor, contactor coil not energised, not closed.
Works only when condensor isolator is turned on.
Leme hear allyuh...

ok you probably heard of single phasing. most 3 phase motors with pump and other high torque starting applications will not start but you would hear a loud hum, but because a fan is already turning it will start to run but it is very loud most times. you can hear the difference in the motor.
from what you describe for this to occur this means your contactor(red phase) is welded together or it has arc enough to be touching on each side
this can occur when you have higher current than the contactor is what we call chattering dropping in and out.
Best bet is to open the contactor and clean the poles . Then once the contacts are not touching any more the fan will not run with the yellow phase disconnected.

This system seems very shoddy. This is why I told you, you need to test each system with a meter. Loads of times we say to ourself the motor/equipment not energised because the contactor open, but here we can clearly see this one is not the case. the blue wire is always energised once the breaker is closed.
the same which happens to the contactor can also happen to a breaker (although much less likely) so it is important to always check with your meter that you have no voltage when you open the breaker.

[hong kong phooey]

I will video it.

Having a hard time understanding how a fan coming on with no power to it (contactor open) and one line disconnected.

I'm getting continuity to ground on the yellow phase with the isolator on though.

Have to check the load cable from the panel breaker to the isolator to see if that damaged and getting continuity to ground there. I made a mistake and checked to ground on the line side of the contactor and the yellow phase read continuity.

will update on details tomorrow, wanna sleep.

Got shocked with the red phase on the load side of the contactor and dismissed it as the capacitor from the fan.
Got shocked again so I assume the contactor closed, took off the cover and it was open. Checked continuity between line and load on each pole, none. Checked to ground (both sides) yellow reads continuity on line side. Thats how I checked continuity by mistake while live.
Got shocked with the signal line for the contactor coil, one side reads 54 V to ground. Air handler off so no signal / voltage should be there.

Sorry i just reading through the post after writing all that.
ok if you said you took off the cover and the contactor was open , was the contacts arced up?, there is a different gapping between the contacts due to the spring. the spring pushes the contacts further apart with the cover off.
with the cover on use your meter see if you have continuity across each phase .
if it was easier to load pictures i would have loaded some pictures to help explain.

As for the part of reading 54V this is possible it depends on how the system is wired . loads of control system have other switches after the contactor and the secondary side of the contactor coil(A2) does not necessarily go directly to neutral/earth.

[hong kong phooey]

Ok
Contactors have the same basic design , a coil to pull the contacts in and spring to push it away (or rarely vice versa)
picture showing spring which will push the contacts apart once not energised. the coil has to overcome the resistance of this spring to pull the contacts together.


ok this is an arced contact
notice the size compare it to a good contact below (same contactor)





once the cover was off on this contactor , the contacts was apart. Once the cover was on, the contacts was touching . This was causing a pump to run even though the stop command was given .

[hong kong phooey]

Blue phase took some heat at one point, insulation burned off.

Another system, isolator burned up badly. Lug welded to ground from arcing.

Common cause of electrical fires . slack connections .
As you know arcing can only occur if the there is a gap between conductors or as they just touch and you the change in potential. tighten all connections

slack connections causes resistance and resistance means more power loss . the higher your resistance the greater your power loss (heat) is current squared multiplied by your resistance.
if you motor was single phasing also this would have caused the current on 2 remaining phases to be higher . also causing excessive heat.

[adnj]

There is the question of where the blue wire is connected. If the inductive motor is 240 V P/P and the high leg may be driving the motor at 208 V P/N. This can cause a high current condition and raise the termination temperature to critical without tripping circuit protection.

Ground wire and neutral wire continuity/isolation should be checked also. Sometimes 3ph is simply not wired properly.

I agree with phooey: There is the chance that the contactor has failed. Some contractors can also be selected for NO or NC. The only way to be certain is to check resistance across the contact.

Your best bet is to sketch the circuit by hand if you want to troubleshoot and track possible failures.

One for the techs in here.
3 phase system, red, yellow and blue wires.
The main breaker supplies 2 3 pole breakers for isolators, one for air handler and one for condenser.
Condenser has a double pole contactor supplying split phase induction type fan motor and three phase compressor, blue line hooked up direct with a lug, red and yellow on line side of contactor, red and yellow on load side of the contactor.
Fan works with yellow wire disconnected from load side of the contactor, contactor coil not energised, not closed.
Works only when condensor isolator is turned on.
Leme hear allyuh...

ok you probably heard of single phasing. most 3 phase motors with pump and other high torque starting applications will not start but you would hear a loud hum, but because a fan is already turning it will start to run but it is very loud most times. you can hear the difference in the motor.
from what you describe for this to occur this means your contactor(red phase) is welded together or it has arc enough to be touching on each side
this can occur when you have higher current than the contactor is what we call chattering dropping in and out.
Best bet is to open the contactor and clean the poles . Then once the contacts are not touching any more the fan will not run with the yellow phase disconnected.

This system seems very shoddy. This is why I told you, you need to test each system with a meter. Loads of times we say to ourself the motor/equipment not energised because the contactor open, but here we can clearly see this one is not the case. the blue wire is always energised once the breaker is closed.
the same which happens to the contactor can also happen to a breaker (although much less likely) so it is important to always check with your meter that you have no voltage when you open the breaker.

[adnj]

Something I am having a hard time understanding and its best I ask here one time:

When you on the ground and you touch a conductor that is carrying current to ground you can get shocked. Arent, you at the same potential to ground and your internal resistance is more than that of the conductor? I understand you wont get the full dose but if you hold a current wire and not touching the ground you don't get shocked. Same way birds dont get shocked.

Well you're right, as far as I understand it also.

If you touch a ground wire that's carrying current to the ground you can get a shock if you are in direct uninsulated contact (barefoot) with the ground. Some amount of current will flow through you and the ground if you are barefoot because you are creating an electrical potential difference between two points. When you are in contact with the ground barefoot you are not really grounded at the same potential as the ground because you are mostly made of water and that creates resistance and thus a potential difference in the circuit. Most of the current will continue to flow in the ground wire. But it only takes 0.1 A flowing across the heart's sinus node to cause atrial fibrillation and a heart attack. If you're wearing proper insulated work boots it should not happen. Always check that your boots are not penetrated by a nail or anything metal. Also there's a standard in the depth they use for ground rods for a reason. http://www.cpuc.ca.gov/gos/GO95/go_95_rule_59_4.html

Current can only flow when there is an electrical potential difference between two points. A bird can't get shocked because all the touching points are the same voltage. If the bird's wing touched another wire while sitting on the bottom wire, it will fry. Because potential difference.

Grounding really means equalizing the voltage across two points. You ever saw videos of helicopter linemen grounding off by attaching the wire to the helicopter first? They're equalizing the voltage across those two points, so now the lineman has no potential difference between him and the wire.

An airplane has static wicks/pins attached all over points on the body and wings that discharges any buildup of electricity that occurs due to lightning or just due to a metal object moving through a magnetic field. The fuselage is designed to act as a Faraday cage to protect everything inside. After a lightning strike they will ground the plane and go over every system with a fine tooth comb before allowing it to fly again.

I never really studied the topic as I'm not an electrical engineer, so disclaimers on that, and willing to be corrected by those who know better.

So my friend you and some of the other posters have the general gist, but allow me to clarify a few areas which should help younto understand grounds...

Grounding does not mean to equalise voltage. The purpose of grounding is to create the path of least resistance for electricity (ie current) to flow in the event that electricity wants to flow anywhere else but within its intended conductors. When current begins to flow in a ground circuit, a potential difference is created.

Secondly, nerve, let me clarify another area. Current does not normally flow in a ground. Current only flows in a ground when there is a ground fault or in other words a part for current to flow through ground. If you ever come across circuits where there is a current in the ground, you have a ground fault. This is why in a properly wired house, you can handle the ground wire with no worries because there will never be current in the ground. Try handling the live wire and you'll get shocked. You can also handle the neutral of a single circuit and not get shocked because neutral is usually grounded in our homes.

So that's why we have GFCI outlets.... In the event that an item is plugged into a GFCI and that item develops a short, ie, a current flow to ground, the GFCI trips to protect the circuit. These are usually resettable. That's why in wet areas like kitchen and bath, GFCIs are mandatory cause the exposure of using an electrical item close to water causes a lower resistance path to ground, due to the water, and increases the likelihood of a ground fault.

This seems to be calling grounding, earthing and bonding the same thing.

[carluva]

Grounding and earthing is the same exact thing.

Bonding has different meanings but when applied to earth, yes, bonding would mean the same. Bonding is actually the connection of a conductor to ground/earth.

[carluva]

I will video it.

Having a hard time understanding how a fan coming on with no power to it (contactor open) and one line disconnected.

I'm getting continuity to ground on the yellow phase with the isolator on though.

Have to check the load cable from the panel breaker to the isolator to see if that damaged and getting continuity to ground there. I made a mistake and checked to ground on the line side of the contactor and the yellow phase read continuity.

will update on details tomorrow, wanna sleep.

Got shocked with the red phase on the load side of the contactor and dismissed it as the capacitor from the fan.
Got shocked again so I assume the contactor closed, took off the cover and it was open. Checked continuity between line and load on each pole, none. Checked to ground (both sides) yellow reads continuity on line side. Thats how I checked continuity by mistake while live.
Got shocked with the signal line for the contactor coil, one side reads 54 V to ground. Air handler off so no signal / voltage should be there.

This sounds very much like an earth fault in that one of the phases are shorting to ground.

A ground fault can be a low current fault - for example a section of insulation on the cable has been burnt, some of the strands of the conductor frayed and these strands simply touching a grounded section of equipment. A small leakage current will flow and generate some potential but the current is not high enough to trip a breaker. This is the most common type of ground faults on commercial and industrial systems.

A ground fault can also be high current - this is a bolted fault and as the name suggests, it's basically a direct connection of a live conductor to ground. This is a high current fault and usually the ones that trip breakers. This is not very common and usually easily identified in a well protected system.

Nerve, if it is a low current ground fault, because of the potential created in the ground, this could be why the equipment is being electrified even though the contactor is open.

My advice is that you should check all wiring and determine if it is a ground fault. Again, that's my initial thought but a video, sketch would help us better.

Also that connection you described from the main breaker is not ideal if there are two cables connected to the load side. It is likely that the breaker rating is higher than the max current carrying capacity of either of the two cables and this is a recipe for disaster. Better wiring is either so separate feeds from two smaller breakers or a single large cable from the main breaker to a splitter and then two smaller breakers with the smaller cables to the respective loads.

[adnj]

Grounding and earthing is the same exact thing.

Bonding has different meanings but when applied to earth, yes, bonding would mean the same. Bonding is actually the connection of a conductor to ground/earth.

Particularly in the case of a 3ph system where many devices are are only 3 conductor, the common misconception exists.

--------

Earthing and Grounding both is refer to zero potential,  but the system connected to zero potential is differ than Equipment connected to zero potential .If a neutral point of a generator or transformer is connected to zero potential then it is known as grounding.

At the same time if the body of the transformer or generator is connected to zero potential then it is known as earthing.

The term “Earthing means that the circuit is physically connected to the ground and it is Zero Volt Potential to the Ground (Earth) but in case of “Grounding” the circuit is not physically connected to ground, but its potential is zero(where the currents are algebraically zero) with respect to other point, which is also known as “Virtual Grounding”.

Earth having zero potential whereas neutral may have some potential. That means neutral does not always have zero potential with respect to ground. In earthing we have Zero Volt potential references to the earth while in grounding we have local Zero Volt potential reference to circuit. When we connect two different Power circuits in power distribution system, we want to have the same Zero Volt reference so we connect them and grounds together.

This common reference might be different from the earth potential.

Bonding is simply the act of joining two electrical conductors together. These may be two wires, a wire and a pipe, or these may be two Equipments. Bonding has to be done by connecting of all the metal parts that are not supposed to be carrying current during normal operations to bringing them to the same electrical potential.

https://electrical-engineering-portal.com/what-is-the-difference-between-bonding-grounding-and-earthing

[nervewrecker]

I want to believe its an earth fault on the yellow phase L2.
Usually you will get difference between two phases when you check the other 2 to ground and a low voltage on the one going to ground.
L2 reads 109 while L1 reads 125 to ground.
The contactor is a month old. Not getting continuity across poles or between poles with it open.
Lugs do not read to ground with power off. Yellow reads continuity to ground with power off (I had checked by mistake and discovered that).
Top discharge commercial system, fan was not in motion in any instance. Checked 3 times. Fan is working with one leg alone and contactor open.
2 out of 3 wires were just rest down in main breaker in panel. Discovered that when I was trying to figure why the system wont start.
Compressor reads 1 ohm between cooks, nothing to ground. Did not have an insulation resistance tester with me.

[hong kong phooey]

Nerve is there a timer in the circuit ?
Normally there is a circuit diagram stuck to the lid of the control box , do you have a picture of that?
is the fan spinning at full speed
this fan is a single phase fan , your compressor is a 3 phase compressor
what you have is a start and run winding on your fan but it is a single phase
trace the wires going to the fan see if there is any relay or another contactor or timer in the cct.

[nervewrecker]

Nerve is there a timer in the circuit ?
Normally there is a circuit diagram stuck to the lid of the control box , do you have a picture of that?
is the fan spinning at full speed
this fan is a single phase fan , your compressor is a 3 phase compressor
what you have is a start and run winding on your fan but it is a single phase
trace the wires going to the fan see if there is any relay or another contactor or timer in the cct.

No timer, timer is on air handler control section. 3 minute time delay to turn on load so as to not have it start on high head pressure. This circuit is on the contactor coil.
No other control devices.
Had a line monitor but that seems to have been condemned.
Fan motor is single phase 220v and it does not spin full speed.
As soon as the isolator turn on you get a burning scent.

[adnj]

You may have a situation where the blue 208V 3ph leg is being transmitted through the winding of the compressor motor. The circuit will complete through the 240 split ph neutral wire of the blower motor.

You are right to want a 3 wire contactor. Perhaps the original compressor motor was split phase.

[hong kong phooey]

Nerve is there a timer in the circuit ?
Normally there is a circuit diagram stuck to the lid of the control box , do you have a picture of that?
is the fan spinning at full speed
this fan is a single phase fan , your compressor is a 3 phase compressor
what you have is a start and run winding on your fan but it is a single phase
trace the wires going to the fan see if there is any relay or another contactor or timer in the cct.

No timer, timer is on air handler control section. 3 minute time delay to turn on load so as to not have it start on high head pressure. This circuit is on the contactor coil.
No other control devices.
Had a line monitor but that seems to have been condemned.
Fan motor is single phase 220v and it does not spin full speed.
As soon as the isolator turn on you get a burning scent.

Exactly the fan is getting one phase from the blue line
the red phase is down ground . some where between the fan and the contactor the red phase has a cut, burn, dig and is making contact to the housing proving a path to earth
this will be enough voltage to run your fan but not at full speed .

coupe things to try with the breaker off disconnect the red phase from the fan and leave the blue side connected. Power on the breaker . does the fan run ?
if the fan runs then you have an issue inside the fan either the terminations touching the housing or internally the fan bad .
if the fan does not run trace the red wire and look for visible damage.

yeah this burning smell is most likely where the red phase is down to earth.
When you open up the fans connection box do you get the burning smell there.

[nervewrecker]

I am also thinking its the blue phase going through the comp motor windings and coming back to the load side of the contactor.
When I got shocked from the red load side of the contactor with it disconnected and breaker off it may have been the fan capacitor discharging.
But im curious as to whats completing the circuit for the fan as it will be the blue phase 208v going to the comp coil and coming back to the yellow on the load sode of the contactor so im getting a 208v (neglecting losses due to resistance across the comp coil) one line on the fan motor. But whats completing the circuit? The second line is disconnected and not connected anywhere. Im thinking that red line from the fan is pinched somewhere and touching the body so its making a ground and completing the circuit as the wire end is loose and hanging mid air. Either that or the motor winding insulation damaged and its going to ground somewhere.
Burnt scent not coming from the motor. Coming from the wires from the isolator to the line side of the contactor.
The earth fault on the yellow phase between main breaker to isolator will explain thr 54V on the signal wire as its one line live and an inline relay on the next to give a 220v to close the contactor coil on the air handler side.
Taxpayers money paid for this sh11ty wiring I should add. Such a disgrace.

[nervewrecker]

What im also not getting is if there is an earth fault on the yellow why am I not getting 220v on the blue and red when measured to ground?

[hong kong phooey]

What im also not getting is if there is an earth fault on the yellow why am I not getting 220v on the blue and red when measured to ground?

ok
what is your incoming phase to phase voltage is it 220 or 440 V?
this voltage depends of the transformer your costumer has. If he getting directly off t&tec three phase he will be getting 208V
if your phase to phase voltage is 220V then your phase voltage to ground is roughly 220/1.73 = 127V
if your incoming phase to phase is 440V then your phase to ground is roughly 440/1.73 = 254 V
remember phase to ground is square root 3 of your phase to phase

[hong kong phooey]

I am also thinking its the blue phase going through the comp motor windings and coming back to the load side of the contactor.

Of course look at your drawing the blue phase will go through your compressor and come back on your other 2 phases . it going to pass through the coil of your compressor and to the red and yellow phases . Remember this is AC the voltage is a sine wave.

When I got shocked from the red load side of the contactor with it disconnected and breaker off it may have been the fan capacitor discharging.
But im curious as to whats completing the circuit for the fan as it will be the blue phase 208v going to the comp coil and coming back to the yellow on the load sode of the contactor so im getting a 208v (neglecting losses due to resistance across the comp coil) one line on the fan motor. But whats completing the circuit?

See my post above
the red wire has to be toughing earth somewhere and most likely where u smelling the burning

The second line is disconnected and not connected anywhere. Im thinking that red line from the fan is pinched somewhere and touching the body so its making a ground and completing the circuit as the wire end is loose and hanging mid air. Either that or the motor winding insulation damaged and its going to ground somewhere.
Burnt scent not coming from the motor. Coming from the wires from the isolator to the line side of the contactor.
The earth fault on the yellow phase between main breaker to isolator will explain thr 54V on the signal wire as its one line live and an inline relay on the next to give a 220v to close the contactor coil on the air handler side.
Taxpayers money paid for this sh11ty wiring I should add. Such a disgrace.

Do you have a make of the unit i could google the unit and get a wiring diagram

[nervewrecker]

220v 3 phase. Lennox 3 tonne
Wiring dia will be the first one i posted.
Driving right now

[nervewrecker]

5uf cap on the fan motor

[nervewrecker]

The air handler coils were destroyed. We can't get air handlers like that to purchase so we put in 2 domestic mini split evaporators and expansion device's.
That's how control voltage is now 220v and not 24v.
Have a vid of the system working.

https://youtu.be/VtxOgcXz2bE

[nervewrecker]

How the original was

[nervewrecker]

Modded.
Its 3 phase delta, 220v. Always was.

[hong kong phooey]

So did you get it working ?

[nervewrecker]

Haven't went back yet. Someone is questioning me and what I know, seems that person knows more than me.
Probably want to spend some money and let their pple get the job to supply new stuff. And when they f**k it up I still have to come fix it just like with every other piece.
As far as I concerned, this system looks ok to startup, its an electrical issue. Thats EFCL area, I cant keep doing their work for them .

[adnj]

Haven't went back yet. Someone is questioning me and what I know, seems that person knows more than me.
Probably want to spend some money and let their pple get the job to supply new stuff. And when they f**k it up I still have to come fix it just like with every other piece.
As far as I concerned, this system looks ok to startup, its an electrical issue. Thats EFCL area, I cant keep doing their work for them .

In your defence, the blower motor should not have been directly wired to any supply if there was to be shutoff controlled by the contactor.

Because the blower motor is split phase with a neutral wire, it can work at a lower speed with a single phase.

Is your drawing showing direct connection to supply for the blower motor and a closed contactor, also?

[nervewrecker]

The pair of evaporators tapped into the circuit the original blower was on. They have their own isolator. Odd enough its also a 3 pole, coming from the main breaker in the panel. Not sure how they wire that or where it joined but it joined somewhere.