Copper/Aluminium Cable Limiters (600Vac)/(250Vac)
By industry definition, cable limiters do not provide overload protection. Class J and Class L fuses for three or more cables-per-phase applications should be considered if overload protection is a concern. This may also be a desirable consideration for aluminum cable using suitable connectors.
Cable limiters applied in utility networks and building power system main parallel service cables are primarily intended to isolate faults in multiple-cables-per-phase installations. This prevents total power outages until maintenance of faulted cable(s) can be scheduled. During the process of opening under fault conditions to isolate faulted cable(s), limiters current limiting action reduces potential for excess heat damage to unfaulted cables.
For applications having three or more parallel cablesper-phase, cable limiters are installed at each end of each cable. For nonparallel or multiple radial cables, limiters may successfully be applied at the source end of each cable for fault isolation.
When analyzing cable limiter potential applications, it is not unusual to forget that normal and abnormal current through cable limiters is divided just as it is between cables.
Selectivity with upstream overcurrent protection devices is seldom of concern. When designing for cable limiter fault isolation to prevent a burn down or unscheduled blackout by one faulted cable, it is desirable to determine the continuous rating load (3 hours or more) that the remaining cables must handle without overheating.
|Voltage Rating||UCL25XX – 75XX, 600Vac UCLA, 250Vac|
|Cable Rating||250MCM to 750MCM Cu - 600Vac; 2/0 or 3/0 Cu - 250Vac; 4/0 Al - 250Vac (Cu/Al terminal required)|
|IR||600V - 200,000 Amps RMS; 250V - 100,000 Amps RMS|
|Agency Approvals||Self-certified to UL requirements.|
- Cable limiters help to a maintain electrical service by minimizing cable damage due to short circuit currents.
- Isolates faulted cable(s) in multiple cables per phase installations.
- Several cable termination types available.
- Residential: 250Vac limiters can be used to protect individual service cables tapped from a single transformer.
- Non-Residential: 600Vac cable limiters should be specified to protect parallel service cables in 120/208Vac, 277/480Vac etc. systems.