ELCI vs GFCI

[aharrigan]

Recently reading Boat US magazine, and if it was safe to swim with a generator on.
One answer was reccommending the use of a ELCI (Equipment Leakage Circuit Interrupter ).
This sound like a GFCI but never heard the term put this way. If there a difference and if so what?

 

[mbrooke]

Not sure about marine installations, but I know earth leakage detectors are common as appliance plugs for window ACs and some older hair dryers.



They monitor the ground wire from the appliance. Should it develop a potential between the hot and neutral or neutral and ground out of spec or it senses excessive current flow through the EGC it opens up the hot and neutral or both hots in the case of 240. Its different from a GFCI in that a GFCI has a ct and looks for current differential between the 2 conductors rather than current or voltage anomalies on the EGC.



Of course Im thinking more along the lines of a cord and plug ELCI than what might be used on marine power.

 

[kwired]

Not sure about marine installations, but I know earth leakage detectors are common as appliance plugs for window ACs and some older hair dryers.



They monitor the ground wire from the appliance. Should it develop a potential between the hot and neutral or neutral and ground out of spec or it senses excessive current flow through the EGC it opens up the hot and neutral or both hots in the case of 240. Its different from a GFCI in that a GFCI has a ct and looks for current differential between the 2 conductors rather than current or voltage anomalies on the EGC.



Of course Im thinking more along the lines of a cord and plug ELCI than what might be used on marine power.

Are you sure it monitors current on the EGC? I did a quick search and didn't find anything yet on how they work, but I would think they would be better off using same technology as a GFCI. They could certainly use a different current level for the trip threshold though. If you lost the EGC for any reason, or never had one to start with, the GFCI technology still will work should current find some other leakage path, but the method you describe likely doesn't see any leakage in that instance because nothing is flowing in the intended EGC in the supply cord.

 

[mbrooke]

Are you sure it monitors current on the EGC? I did a quick search and didn't find anything yet on how they work, but I would think they would be better off using same technology as a GFCI. They could certainly use a different current level for the trip threshold though. If you lost the EGC for any reason, or never had one to start with, the GFCI technology still will work should current find some other leakage path, but the method you describe likely doesn't see any leakage in that instance because nothing is flowing in the intended EGC in the supply cord.

Wellp, at lest the ones Ive seen. GFCI technology is by far the most common and reliable.

Marine power isnt my area of knowledge, however the ELCIs (LCDI) that I am familiar with have a circuit board and a wire that monitors the internal parts/ insides/frame or cord for leakage. Often this wire looks for an elevated voltage compared to the ground or neutral. Other versions monitor the EGC. Both version will trip if the wire being monitored goes out of normal specs. These are getting rarer but were used on some older hair dryers and select appliances.Why this was done over a GFI Im not sure, but most likely just an inverter/manufacturer coming up with a different way to monitor an for appliance leakage.


Doing I quick Google search I found this thread that gives on example of an LCDI. In this case it appears the LCDI is monitoring the cord only. If you look at the power cable you will notice wrapped around the hot, neutral and ground a cooper mesh wire that is then soldiered to the logic board. If the hot was damaged internally in the cord it would short to the mesh and trip out the LCDI. Usually the concept is done to the appliances internal parts or frame but in this case its the cord. Similar concept though:

http://www.homebrewtalk.com/f170/gfci-vs-lcdi-321139/

 

[mbrooke]

*Inventor lol. My auto correct knows me all to well:lol:

 

[renosteinke]

There are a variety of GFCI-like devices out there, made for use as part of specific listed equipment. For example, window air conditioners have their "LCDI," and hair dryers have their gizmo.

Then there's the use overseas of the "RCD" at the service entrance.

There are AFCI's, which supposedly also have a GFCI component - but are NOT approved for use as GFCI's

Finally, there are specialty GFCI's with trip levels different from the usual 4-6mA setting of the ordinary GFCI.

I don't know anything about the item you name - but the code says GFCI, so GFCI it must be.

 

[kwired]

There are a variety of GFCI-like devices out there, made for use as part of specific listed equipment. For example, window air conditioners have their "LCDI," and hair dryers have their gizmo.

Then there's the use overseas of the "RCD" at the service entrance.

There are AFCI's, which supposedly also have a GFCI component - but are NOT approved for use as GFCI's

Finally, there are specialty GFCI's with trip levels different from the usual 4-6mA setting of the ordinary GFCI.

I don't know anything about the item you name - but the code says GFCI, so GFCI it must be.

We are talking about leakage current detectors that typically are part of a listed appliance, usually part of the cord cap assembly. They seem to be common last few years on window air conditioners, and on hair care appliances, maybe a few other appliances but those are the ones I have noticed the most. It has nothing to do with NEC but rather product safety or listing requirements.