An Unnecessary Investment Avoided
At one of the sites operated by a nationwide telecommunications provider, the electrical protection system was tripping intermittently — specifically, one of the circuit breakers at the electricity meter would disconnect.
Because the fault appeared to occur randomly, increasing the available electrical capacity was considered.
Submetering, however, showed that the problem was not insufficient overall capacity. A piece of technical equipment was periodically overloading one phase.
After adjusting the equipment settings, the tripping stopped — without any electrical capacity upgrade.
The starting point
The site had a 3 × 32 A electrical supply. During operation, one of the phase circuit breakers would occasionally trip, seemingly without any clear pattern.
Because the problem occurred only intermittently, it was difficult to identify during a conventional on-site inspection.
The obvious explanation seemed to be that the available electrical capacity was simply insufficient for the site.
As a result, increasing the available capacity and upgrading the electrical connection had already been considered.
Before starting a costly investment, however, it was worth finding out what was actually happening in the electrical system.
What did we measure?
We measured the main consumption groups separately, including:
the technical equipment;
the air-conditioning systems;
the total incoming supply.
Using submetering, we continuously monitored the load on all three phases and then analysed the load profiles of the individual circuits during the problematic periods.
On one occasion, the measurement captured a condition where the current on one phase remained close to the 32 A limit for an extended period.
This was the point where the previously seemingly random breaker trips became measurable and traceable.
What did submetering reveal?
Phase imbalance and avoided electrical capacity upgrade – OMS24 Zrt.
The upper chart shows the load on the three phases at the site’s incoming supply.
A period can clearly be seen where the load on one phase approaches 32 A, while the total load is not evenly distributed across the three phases.
The lower chart shows the operation of the technical equipment responsible for the problem.
The measurement revealed that this equipment was causing the intermittent phase imbalance.
There were operating periods when the equipment placed most of its load on only two phases.
When the site’s air-conditioning system started at the same time, the current on one of the phases could easily approach the 32 A limit for the entire site.
Because the technical equipment periodically rotated this operating condition between phases, the breaker trips appeared to occur randomly on different phases.
After the equipment settings were changed, the final section of the upper chart — showing the total incoming supply — already demonstrates significantly more balanced operation.
What was causing the problem?
The measurement data allowed us to trace the problem back to a three-phase piece of technical equipment.
Its operating logic periodically changed the way it loaded the individual phases.
As a result, one phase could temporarily carry a significantly higher load than the other two.
In other words, the problem was not that the site required too much power overall.
The problem was how the available capacity was distributed between the phases.
This is an important distinction.
If the total available capacity is genuinely insufficient, an electrical capacity upgrade may be justified.
If the problem is phase imbalance, however, the first step should be to correct the load distribution.
What did we change?
We disabled the function in the technical equipment that was causing the unfavourable changes in phase loading.
After the adjustment, the load became more evenly distributed across all three phases.
No electrical capacity upgrade was carried out.
No increase in available supply capacity was required.
A change in the equipment settings solved the problem.
The result
Following the intervention, the circuit-breaker trips stopped, and the previously considered capacity upgrade was no longer necessary.
Investment avoided
Breaker trips eliminated
More balanced phase loading
In this case, the value of submetering was not primarily measured in saved kilowatt-hours.
Its value was in avoiding an investment that would not have addressed the real cause of the problem.
The lesson
A tripping circuit breaker can easily lead to the conclusion that the available electrical capacity is insufficient.
However, a one-time on-site measurement may not reveal a fault that occurs only under specific operating conditions.
Continuous measurement does more than show how much energy a system consumes. It can also show how the system actually operates.
Sometimes, that is the difference between a major new investment and a simple technical adjustment.
Do you have electrical problems at your site whose cause remains unclear?
Submetering can be used not only to analyse energy consumption, but also to examine the behaviour of the electrical network and connected equipment in much greater detail.