Mike Dolt Enterprises
Mike Dolt Enterprises
User: mark32, Location: Currently in NJ
Asked on: Wednesday, February 26, 2025 at 6:27 pm EST
Answered on: Thursday, March 6, 2025 at 9:08 am EST
Question: Hello all,I am trying to troubleshoot this circuit, as the breaker will trip after a few seconds, but I am unsure what I'm supposed to be looking for. In this photo, (Which was taken after we started troubleshooting) you will see the black from the clock's pigtail is together with a lead that goes to that relay. These tie together with the feed (black 120vac) coming in and going out to the rest of the clocks. We are getting continuity to ground on one of the red conductors. (I believe this red conductor is the one that is used to synchronize the clocks). So okay, now we have something to look for. However, what is actually suppose to take place here? I am told 24vdc is applied to the red conductor, (for synchronizing purposes) but how does this occur? You can see some LV wiring on the bottom of the relay, which I assume originates at the master clock two floors above. The relay itself is labeled as such, the "input" is the LV and the "output" are the black and white/red conductors. Initially, I thought once the control wiring closed the relays contacts, 120v would be applied to the white/red conductor, but this is not the case, at least I don't think it is. But, it must be the case, which is why the breaker is tripping. Can anyone shed some light on this for me?
Okay, let's break this down. You've got a classic, but potentially confusing, synchronized clock setup. Here's a breakdown of what's likely happening and how to troubleshoot it
Understanding the System
Master Clock
Located two floors above, generates the synchronization signal (likely a timed pulse of 24VDC).
Slave Clocks
Receive the synchronization signal from the master clock and adjust their time accordingly.
Synchronization Wiring
The low-voltage wires (originating from the master clock) carry the 24VDC synchronization signal.
Relay
This is the crucial component. Its purpose is to connect the sync wire when triggered. The input is the LV that originates at the master clock, the output is the "red conductor" that is sending the sync pulse down the line.
Why the Breaker is Tripping
The fact that the breaker is tripping and you have continuity to ground on the red conductor strongly suggests that you have a short circuit between the red (synchronization) wire and ground, which is likely caused by the relay incorrectly wiring the 120v. It's highly likely that one of the clocks down the line is damaged and is shorting the red wire to ground.
Troubleshooting Steps1. Confirm the 24VDC Signal
Go to the Master Clock
Verify that the master clock is indeed outputting a 24VDC signal on the synchronization wires. Use a multimeter to check the voltage between the synchronization wires coming from the master clock. If it's not outputting 24VDC, the problem is with the master clock.
Check the Wiring
Carefully examine the wiring between the master clock and the input side of the relay. Ensure there are no breaks, loose connections, or shorts to ground.2.
Isolate the Problem
Disconnect the Red Conductor at the First Clock
Go to the first clock after the relay in the circuit. Disconnect the red wire at the first clock. This isolates the downstream clocks and wiring. Re-energize the circuit.
If the Breaker Still Trips
The problem lies between the relay and the first clock. Carefully inspect the wiring, conduit (if applicable), and junction boxes.
If the Breaker Doesn't Trip
The problem is downstream of the first clock.
Systematically Reconnect Clocks
One by one, reconnect the red wire to each clock, re-energizing the circuit after each connection. When the breaker trips, the last clock you reconnected (or the wiring leading to it) is the culprit.3.
Inspect Suspect Clock(s) and Wiring
Visual Inspection
Look for obvious signs of damage: Burned wires Cracked insulation Water damage Loose connections Anything that looks out of place
Continuity Testing
With the power OFF and the suspect clock disconnected from the red synchronization wire
Use a multimeter to check the continuity between: The red wire connector and the clock's metal chassis (or ground wire). You should NOT have continuity (infinite resistance). Continuity here indicates a short. The red wire connector and the neutral wire. You should NOT have continuity. The neutral and ground. Should be continuity.4.
Examine the Relay Closely
Wiring Verification
Carefully trace the wiring connected to the relay. Ensure it matches the relay's schematic (if available). Make sure the low voltage is connected to the input, and the outputs are going to the correct wires.
Relay Functionality
Test the relay itself. With the 24VDC signal applied to the input, use a multimeter to check for continuity between the output terminals of the relay. It should only have continuity when the 24VDC signal is present.
Isolate the LV from the red conductor wiring the neutral is likely tied in at the relay.5. Consider Conduit and Junction Boxes
If the wiring runs through metal conduit, check for chafing or damage where wires pass through the conduit. Inspect junction boxes for loose connections, water damage, or other issues.
Important Safety Precautions Work with the Power OFF
Always disconnect the power to the circuit breaker before working on the wiring.
Use a Multimeter
A multimeter is your best friend in this situation. Learn how to use it to test for voltage, continuity, and resistance.
Proper Tools
Use insulated tools designed for electrical work.*
If You're Unsure, Call an Electrician: If you're not comfortable working with electrical wiring, it's always best to call a qualified electrician. Electrical work can be dangerous.Let me know if you have any more information or questions as you work through these steps! Flag for review