I gave my customer VD. Can I take it back?

[ritelec]

Scenario:

One 50 amp sub panel (single phase three wire, 240v, fed with #8 ac), fed from 200 amp service.
From what I see, it looks like an existing 8 wire was used for a kitchen reno which the previous electrician installed this panel for.
He has the refrigerator and other circs going back to the main panel, but is feeding the micro, dw, some lighting (5 high hats and maybe some LV undercabs)...from this panel.

New pavers were installed for an existing pool. The original area around the pool was concrete. To remove concrete they jack hammered etc... which broke the conduits and wiring
which fed a pool pump and pool light (one 240v pump, one 120v light) from the 200 amp service.

I was directed to feed a new pool pump (240v 9.5 amps) and a new LV pool light from the 50 amp sub panel which I did.

The owner called and said his kitchen lights dimmed for a couple of seconds which they never did before.
He had the lights on, the microwave, the dw, and the pump running.
He said all was fine until the end of the dw cycle and dw turned off and lights dimmed.. (I think the dw turning off was coincidental but...).

My only thought at this time is to check into the panel, and if the kitchen 120v micro, dw, lighting...and what ever else I may discover, is heavy on one of the phases is to split
them up alittle more between the two phases.

With the total load as it is now.... if I come up with maybe 32 amps on a single phase with all running, with vd internet calculations. it doesn't seem like there should
be a sufficient vd for these lights to dim (70 to 100 feet at the most from main panel to sub panel, then 30 feet from sub panel to each load...).

My question is, if this doesn't correct the dimming, I'm leery as to talk to this gentleman about what ever it may take to get the new pump motor to be
fed from the main 200 amp service, as I've noticed that many times in alot of homes (and other places) that occasionally when an air conditioners
kicks on, whole house and or wall/window units, fed from separate circs., lighting on separate circuits still dim.

To talk to him about re-feeding the pump from the service, then to have the lights dim anyway would not be good and a bit embarrassing.

??????......... Might shedding the loads in that sub-panel eliminate the dim?
Why do air-conditioners on separate circ's sometimes dim lighting on separate circs.?

Thanks all for any input....

Rich

 

[iwire]

I suspect that when the dishwasher 'stopped' it really just stopped making noise and went into a heated dry cycle. That draws the most current of the dishwasher cycles.

It sounds like you have a straight up VD issue due to relocating the pump feed from the main over to this sub panel.

Has he mentioned any lights getting brighter?

If so that would point to a bad neutral connection.

 

[ritelec]

Thanks iwire.........

Not sure if the dw stopped, or went to heat..........he said it stopped and beeped.......


beep beep.......

:- )

 

[kwired]

When an air conditioner or other motor causes dimming of lights throughout the house it is usually voltage drop on the service or feeder and nothing wrong with the wiring inside the structure. It could even be voltage drop in POCO transformer if it is a small transformer. Remember motors draw high current when starting across the line but it rapidly drops as the motor accelerates.

Instead of re-feeding the pool pump maybe you should consider re-feeding the lights that are effected by the voltage changes.

And instead of installing a new circuit only to find out the problem still exists, maybe try a temp supply first to check out the performance before putting a lot of time into something that still doesn't get what is wanted.

 

[ritelec]

Thank you

 

[curt swartz]

This existing sub panel is fed with AC cable? Most AC cable does NOT have a separate grounding conductor. If this cables doesn't have a separate grounding conductor you can't use it to supply swimming pool equipment (680.25).

 

[hurk27]

This existing sub panel is fed with AC cable? Most AC cable does NOT have a separate grounding conductor. If this cables doesn't have a separate grounding conductor you can't use it to supply swimming pool equipment (680.25).

Curt take a look at 680.21(A)(4)

Edited that I see this only applys to branch circuits to motors, My bad.

For some reason I thought it was allowed for feeders in dwellings as an exception?

 

[ritelec]

You guys got me looking.............I should be ok (except for the VD)......with the "insulated ground" right???

Main panel (interior) > sub panel (type ac - no insulated ground) (interior) > pool panel (mc to pvc - insulated ground) (interior to exterior) > branch circs to equipment (insulated ground)
??????

thanks

 

[ritelec]

Re Reading..........as of 680.25 this may be wrong.........
Please clarify .

Rich.

 

[iwire]

When an air conditioner or other motor causes dimming of lights throughout the house it is usually voltage drop on the service or feeder and nothing wrong with the wiring inside the structure. It could even be voltage drop in POCO transformer if it is a small transformer.

Apparently that is not the case here as the info we were provided seems to indicate it was not a problem until the pump feed was relocated to the sub panel.

 

[kwired]

When an air conditioner or other motor causes dimming of lights throughout the house it is usually voltage drop on the service or feeder and nothing wrong with the wiring inside the structure.

Apparently that is not the case here as the info we were provided seems to indicate it was not a problem until the pump feed was relocated to the sub panel.

Correct. The change was made on the feeder in this case and the feeder is where the problem is.

 

[ritelec]

Curt take a look at 680.21(A)(4)

Edited that I see this only applys to branch circuits to motors, My bad.

For some reason I thought it was allowed for feeders in dwellings as an exception?

And looks like any branch circ wiring would still require a ground conductor..........I can't tell....

Any wiring method in chapter 3 then turns around and mentions ground conductor installed in cable assembly.

Please correct me if I have this wrong.
armor clad no ground wire n/g.
emt, rigid metal etc.... no ground n/g.

Feeder or branch circuit. No ground "conductor" n/g. Correct?

thank you

 

[kwired]

And looks like any branch circ wiring would still require a ground conductor..........I can't tell....

Any wiring method in chapter 3 then turns around and mentions ground conductor installed in cable assembly.

Please correct me if I have this wrong.
armor clad no ground wire n/g.
emt, rigid metal etc.... no ground n/g.

Feeder or branch circuit. No ground "conductor" n/g. Correct?

thank you

I did not look into the quoted section, but I think the point was that swimming pool equipment needs an actual copper grounding conductor, AC cable has a sheath rated for use as an EGC but would not be acceptable for use as the sole equipment grounding conductor in places where a copper conductor is required.

 

[StarCat]

Microwaves

Microwaves

Every microwave I have ever worked with pulls 15 AMPs when running.
They are major offenders, and also quite a bad idea to even have, but try to convince anyone of the real facts about them.
People are hooked on them and don't seem to realize that what comes out is no longer food.
We used to install hard start gear on scroll compressors in the 90s because of the ole dimming light complaint to lower peak inrush.
Scrolls were not supposed to need hard start by the book back then.

 

[iwire]

Every microwave I have ever worked with pulls 15 AMPs when running.
They are major offenders, and also quite a bad idea to even have, but try to convince anyone of the real facts about them.
People are hooked on them and don't seem to realize that what comes out is no longer food.

That is interesting to say the least.

 

[kwired]

Every microwave I have ever worked with pulls 15 AMPs when running.
They are major offenders, and also quite a bad idea to even have, but try to convince anyone of the real facts about them.
People are hooked on them and don't seem to realize that what comes out is no longer food.
We used to install hard start gear on scroll compressors in the 90s because of the ole dimming light complaint to lower peak inrush.
Scrolls were not supposed to need hard start by the book back then.

Not sure just where you are getting information from, for it to pull 15 amps it would have to be at least 1400+ watt unit, would depend on power factor and efficiency of unit to get exact ratings. Largest units I can recall seeing are only 12-1300 watts.

If you are talking about major offenders when it comes to voltage drop, anything else with similar load rating will be just as offending.

I do agree they are not the best thing to cook with, but to just heat something up they work just fine. I don't think there is much microwave leakage to a unit that has not been tampered with or destroyed, the microwaves do not change the food, they just add energy in the form of heat to it.

Hard starts on compressors will only make current draw even higher - but for shorter duration. All they are is a bigger capacitor put into the circuit to create greater phase shift to give more starting torque and controls to switch it out of circuit when it is no longer needed. This will mean more starting current, but faster acceleration so the duration of the higher current will be less time than without the hard start kit.

 

[ritelec]

Ok .....

Can't get my head around this.

I fed an exterior intermatic single phase panel with time clocks with 10-3 mc in the building 15' or so to the panel fed with the ac.
I stripped the mc and chased it thru the 3/4 " pvc to the exterior intermatic panel... The wire in the mc being thhn/thwn I should be ok there right?

Now, inside the building I plan on splicing the 10-3 mc to 10-3 mc run to the main panel. Should be good right?

Would it be permissible to splice the 10-3 mc to 10-3 nm back to the panel instead of 10-3 mc?




Thank you.

 

[kwired]

Ok .....

Can't get my head around this.

I fed an exterior intermatic single phase panel with time clocks with 10-3 mc in the building 15' or so to the panel fed with the ac.
I stripped the mc and chased it thru the 3/4 " pvc to the exterior intermatic panel... The wire in the mc being thhn/thwn I should be ok there right?

Now, inside the building I plan on splicing the 10-3 mc to 10-3 mc run to the main panel. Should be good right?

Would it be permissible to splice the 10-3 mc to 10-3 nm back to the panel instead of 10-3 mc?




Thank you.

I don't see why not.

I really wish you used a different thread title, every time it appears in the what's new list, I keep thinking you and your customer both need to see a doctor:lol:

 

[PetrosA]

I don't see why not.

I really wish you used a different thread title, every time it appears in the what's new list, I keep thinking you and your customer both need to see a doctor:lol:

I was wondering if I was the only one thinking that... :ashamed:

 

[ritelec]

Thanks kwired.........

Yes, the plot has thickened.....

Turns out, the home owner had recently had his kitchen redone. I went in last week to repair broken exterior pool conduits.........(actually, there gone)
I fed an exterior intermatic panel from the interior sub panel fed with type ac.

The owner had final inspections today (electrical included) and the inspector noticed the ac fed kitchen panel with a two pole circuit labeled pool. :jawdrop:

Please to confirm..............I can most definitely use type nm (no insulated ground) to extend that mc circuit back to the main panel with no further
embarrassment. :ashamed:

I would use the mc if need be, but it was a great dog getting a few snakes from the main to that sub panel point and the nm may make life alittle easier.

Thanks again.

Rich