Overcurrent protection

[hhsting]

I have 8#14 for low voltage signaling cable. I have engineer that claims no overcurrent protection is required for cables. However I am not sure. Does NEC 2017 require overcurrent protection for such cables?

 

[jim dungar]

The NEC does not define low voltage.
Are these power limited circuits?

 

[hhsting]

The NEC does not define low voltage.
Are these power limited circuits?

These are fed from fuel oil tank monitoring control panel but not sure about power limited circuits???

 

[steve66]

If they are fed from a control panel, doesn't the control panel have OCP on its supply? Wouldn't that protect the conductors?

I lot of PLC outputs are often individually fused, but that's usually more for reliability and protecting the PLC components, and probably not any code requirement.

 

[don_resqcapt19]

It is not typical to have overcurrent protection on these circuits, other than stated by Steve above, to protect the control system itself and not to protect the conductors.

 

[hhsting]

If they are fed from a control panel, doesn't the control panel have OCP on its supply? Wouldn't that protect the conductors?

I lot of PLC outputs are often individually fused, but that's usually more for reliability and protecting the PLC components, and probably not any code requirement.

Control panel is fed from 20A breaker. I dont see 20A breaker protecting #14 awg?

 

[Rock86]

Control panel is fed from 20A breaker. I dont see 20A breaker protecting #14 awg?

Are the #14 awg after the control panel? Look at the design from the 20A breaker to the control panel... what is the conductor size?

 

[hhsting]

Are the #14 awg after the control panel? Look at the design from the 20A breaker to the control panel... what is the conductor size?

Yes #14 awg after control panel ie fed from control panel. The cable from control panel to 20A breaker is #12 awg.