Length of conductor on GFCI breaker

[hardworkingstiff]

I read a note in the SQ D digest that said we should not run the conductors fed from a GFCI breaker longer than 250' (one way) to avoid nuisance tripping.

Has anyone dealt with this? Have you had a problem in the past?

The reason I'm asking, I'm looking at ways to comply with 555.3, and one way is to install GFCI breakers, but if nuisance tripping will be a problem, it's not a solution. The conductor runs will be over 400' (one way).

Any comments are appreciated.

 

[Dennis Alwon]

I would not install a gfci at the panel on long runs as it will causes problems. Can you install a dead front gfci at the end of the run? What are you wiring?

 

[ptonsparky]

I believe 555.3 refers to Ground-Fault protection and not GFCI protection. A difference of about 96 mA.

 

[hardworkingstiff]

I would not install a gfci at the panel on long runs as it will causes problems. Can you install a dead front gfci at the end of the run? What are you wiring?

I've used those before, but it won't work here. An existing dock that wants to relocate 1 power center and install 2 new ones (shore power for boats). Just the circuits modified will need to have GFP on them, and we are trying to keep the price down. I was considering GFCI breakers, but it looks like I'll just have to install a GF monitoring systems and control shunt trip breakers.

 

[hardworkingstiff]

I believe 555.3 refers to Ground-Fault protection and not GFCI protection. A difference of about 96 mA.

Yea, it's kind of weird, since 100ma does not offer personnel protection, what's the purpose?

I've had discussions with a couple of people about this and it seems there is a lack of consensus.

 

[kwired]

Capacitance in the long conductors can lead to enough leakage current to cause undesired tripping of a GFCI, is the reason it is not recommended for long runs. If the GFCI is near the load end of a long run then the GFCI does not have to monitor such a long circuit which will have less capacitance.

 

[ptonsparky]

Yea, it's kind of weird, since 100ma does not offer personnel protection, what's the purpose?

I've had discussions with a couple of people about this and it seems there is a lack of consensus.

I believe you would still need the GFCI protection at the end of, or along the way as you tap it.

 

[kwired]

I believe you would still need the GFCI protection at the end of, or along the way as you tap it.

Yes the personnel protection is on the branch circuits not the feeder.

 

[cpinetree]

Shore power or 15/20 amp 110v?

Shore power or 15/20 amp 110v?

I've used those before, but it won't work here. An existing dock that wants to relocate 1 power center and install 2 new ones (shore power for boats). Just the circuits modified will need to have GFP on them, and we are trying to keep the price down. I was considering GFCI breakers, but it looks like I'll just have to install a GF monitoring systems and control shunt trip breakers.

If it is just shore power (30a 125v / 50a 250v) you do not need a GFI.
2011 555.19(B)1 only requires GFI for the 15 + 20a 125v receptacles.
If the boat needs the shore power for bilge pumps etc. a tripped GFI could possibly result in a sunken boat.

 

[kwired]

If it is just shore power (30a 125v / 50a 250v) you do not need a GFI.
2011 555.19(B)1 only requires GFI for the 15 + 20a 125v receptacles.
If the boat needs the shore power for bilge pumps etc. a tripped GFI could possibly result in a sunken boat.

I did not look into it, but have a hard time believing a sunken boat takes precedence over someone being electrocuted.

 

[cpinetree]

Scary but true

Scary but true

I did not look into it, but have a hard time believing a sunken boat takes precedence over someone being electrocuted.

Hard to believe but true. We will often use a GFI on the shore power receptacles anyway, as long as the boat is on a lift. If it is a larger boat 40'+ and no lift then No GFI.

 

[hardworkingstiff]

If it is just shore power (30a 125v / 50a 250v) you do not need a GFI.
2011 555.19(B)1 only requires GFI for the 15 + 20a 125v receptacles.
If the boat needs the shore power for bilge pumps etc. a tripped GFI could possibly result in a sunken boat.

But now 555.3 requires GFP not to exceed 100ma for the service main, or all feeders leaving the service panel.

I'm wiring 50 and 30 amp receptacles (shore power for boats), so only the 100ma GFP is required.