2. tech-talk
  3. 154986-2280

Equi=Core Hum & Other Issues

I’ve owned a Core Power Tech Equi=Core 1800 for 6 months. Recently the transformer has started to hum inside the chassis. It happens when components are on and also when sources are powered down. The transformer hum is intermittent. It ranges from multiple times per day to 3 or 4 days without any hum. I never had DC on my dedicated lines before, so I picked up a Klein Tools AC/DC tester... https://www.kleintools.com/catalog/electrical-testers/electronic-acdc-voltage-tester-12-240v-ac-15-2...
and when plugged into wall receptacles it indicated overload. Line voltage is steady at 122VAC and always has been.
What am I doing wrong, and how should I test for DC on the power line?

I discovered another problem when testing the Equi=Core duplex receptacles; they indicate inverted polarity. All house outlets measure correct polarity.
I’m looking for some assistance in diagnosing this hum. I’m not sure if it’s due to DC offset or if the torroid itself is vibrating in its mounting.

I know this is becoming a long thread, but I must mention that the Equi=Core now trips the breaker at the panel when powered on. It trips several times in a row, eventually allowing power-up. This is a 20A dedicated line from a subpanel which I’ve had for years.
Any advice is much appreciated.


128x128lowrider57
lowrider57's avatar
lowrider57 OP
5,417 posts
 
@jea48 ,
I plan on having the entire outside cable run plus meter lid replaced. The cable from meter to service panel was inspected and is ok.

Service panel is an older unit, the previous owner had about 80% of branch circuits replaced. It's easy to spot these...new breakers and cables. The old wiring runs to low current draw areas such as bedrooms, light fixtures. I had my electrician strip wires and organise the panel to keep an even load on each leg. 

I extended the service to include a subpanel with (2) 20A lines, 12/2 Romex, hospital-grade duplexes.
8' ground rod off main panel with second ground rod from subpanel. Most of the homes are grounded to plumbing.

uberwaltz's avatar
uberwaltz
13,381 posts
 
Am I missing something here?
Surely all of this should be on the electric company provider to make good and safe?
Here if I was even to look at anything on the incoming side of my main panel JEA would likely have me hung, drawn and quartered!
jea48
4,486 posts
 
I plan on having the entire outside cable run plus meter lid replaced. The cable from meter to service panel was inspected and is ok.
The cable from meter to service panel was inspected and is ok.
@lowrider57

Inspected by who? The city AHJ?

In my city.
Any time a new electrical service is installed an electrical permit must be pulled by a licensed electrical contractor that is licensed to do electrical work in the city.

Minimum overhead fed electrical service required for a single family dwelling unit is 100 amp.
Is the cable/wire rated for a service entrance rating of 100 amps? In my area, before the Utility Power Co will hook up the new electrical service the City AHJ must release the new service for a hook up.

What all was the electrical contractor/electrician that gave you a price of $2000.00 going do? Was he going to re use the old cable from the new meter socket to the existing electrical panel?

Jim
lowrider57's avatar
lowrider57 OP
5,417 posts
 
@jea48 ,
At first, the electrician wrote an estimate for $2500 which included all outside replacement plus meter to panel cable.
He then examined the cable from meter to panel and said it didn't need replacement, so changed amount of estimate. 

Service for this 2 story rowhome is 60A.
Don't need a permit for inside work; electric or plumbing. 
For this outside job, contractor will get permit and contact power company.

Building inspector is only required by mortgage company during sale of a house in Philadelphia. It was inspected when I made the purchase. It passed with the old wiring and ground to water main.


jea48
4,486 posts
 
uberwaltz11,178 posts

05-04-2020
7:18pm

Am I missing something here?
Surely all of this should be on the electric company provider to make good and safe?
Here if I was even to look at anything on the incoming side of my main panel JEA would likely have me hung, drawn and quartered!
@uberwaltz

It depends where you live who owns what and who is responsible for what. In lowrider57 case he owns, is responsible for, the service drop, meter socket, and service entrance wiring from the meter socket to his electrical service panel. He is also responsible for the system grounding as well, (grounding electrode system).


cleeds2,926 posts

04-22-2020
9:47am

lowrider57
... the corrosion in my meter box is causing distortion in the mains.
That’s potentially hazardous. Your electric utility should install a new meter and/or meter pan, as needed.
Does anybody know if a toroidal transformer can be damaged due to longterm hum from harmonic distortion?
That seems unlikely.



lowrider57 OP3,684 posts

04-22-2020
10:26am

Seems unlikely?
Thank you @cleeds .

That’s potentially hazardous. Your electric utility should install a new meter and/or meter pan, as needed.

I know. Unfortunately, the homeowner is responsible for the maintenance of the meter pan and meter drop onto the property.
There’s a water leak in the conduit from my roof down to the meter and the seal into the pan has worn away. The estimate from an electrical contractor is $2000 and money is tight right now. I need to get some more estimates.

More to discover