Maximum circuit length

[M.ABDULLATIEF]

I have a project which has all branch circuit fed from MCCB, how to calculate the maximum length for the circuits to be protected with the circuit breaker

 

[ptonsparky]

A 15 amp CB can protect a 2000' circuit.

You need to give us more information. What size wires? What is the current? How long? VD constraints?

 

[M.ABDULLATIEF]

i need a general equation or rule to calculate the maximum allowable length, based on voltage drop it's ok for me to calculate, but i need this query regarding to short circuit protection in breaker,

in my current case I have 16A MCCB with below attached TCC, and the wire size is 4mm2 Cu/LS0H, the voltage system is 230/400 V, the length i want to check is 190m is ok or not?

 

[Fred B]

A 15 amp CB can protect a 2000' circuit.

You need to give us more information. What size wires? What is the current? How long? VD constraints?

also AFCI GFCI have a length limit for the circuit. 210.12(A)(3),(4).
Voltage drop over the distance can negatively effect the operation.

 

[Fred B]

i need a general equation or rule to calculate the maximum allowable length, based on voltage drop it's ok for me to calculate, but i need this query regarding to short circuit protection in breaker,

in my current case I have 16A MCCB with below attached TCC, and the wire size is 4mm2 Cu/LS0H, the voltage system is 230/400 V, the length i want to check is 190m is ok or not?

Are you trying to minimize the AFC?

 

[M.ABDULLATIEF]

no. it's normal circuit and the consultant refuse to approved any circuit exceeding 150m.

 

[jim dungar]

Is this for North American installations? You mention short circuit protection and you show a European breaker curve.

In the US and Canada, we do not need to worry about conductor and breaker coordination because of the way our products are extensively tested together to a single standard by a testing agency like UL. We simply need to match the nominal rating of the breaker with the ampacity of the conductor based on the tables in our National Electrical Codes.

About the only circuit length concern we have is voltage drop.

 

[M.ABDULLATIEF]

this project in middle east region

 

[ptonsparky]

no. it's normal circuit and the consultant refuse to approved any circuit exceeding 150m.

Then that is their prerogative. IDK how you get there if it's 151, but it's their choice if they are signing the check.

 

[don_resqcapt19]

also AFCI GFCI have a length limit for the circuit. 210.12(A)(3),(4).
Voltage drop over the distance can negatively effect the operation.

There is no length limit for GFCIs, the the AFCI limit is only very a very specific installation method using an AFCI receptacle.