GFCI, AFCI for Furnace

[hbiss]

PaulMmn[/B]]It all depends... what kinds of arcs do the AFCIs detect? I just had my furnace overhauled last night. It's a fuel oil furnace. Oil is pumped through a spray nozzle into the combustion chamber, where the 120 volt supply is boosted through a transformer to create an electric arc of between 10,000 and 14,000 volts which zaps the oil mist to make sure it ignites. It appears there are two versions-- one with a continuous arc, the other just until the photoelectric sensor sees the light of the burning fuel.

Wont detect an arc on the other side of an isolation transformer, probably not through an autotransformer either.

However AFCI and even GFCI's can be subject to tripping if there is any inductive kickback produced in the application. Which is often kind of random trips rather than predicable trips when this happens.

Actually transformers aren't used anymore for oil burner ignition. I replaced mine several years ago with a small solid-state igniter when the transformer went bad. So I suspect you can expect similar problems to what you experience with gas range igniters.

Most all residential burners use continuous ignition. I'm sure they do make a primary control that will do intermittent ignition like Paul mentions also. In all cases the photo cell monitors the flame to make sure it has ignited and stays ignited. If it doesn't see a flame within 15 seconds of starting and anytime thereafter for 15 seconds, it shuts down the burner and you have to press the reset button. This so you don't have your combustion chamber filled with oil.

-Hal

 

[mbrooke]

Yes, but the furnace room is not one of those rooms.

 

[hbiss]

Agreed.

-Hal

 

[mlnk]

Here is my thinking on AFCIs. Sorry, could not eliminate bold print...
2017 NEC - WHERE AFCI NOT REQUIRED

The remaining areas where AFCI protection is not required and is optional are: Garages ( if laundry area is in garage, AFCI for laundry area only).
Attics, crawl space, uninhabited basement areas.
Outdoor receptacles and outdoor circuits.
Sump pumps and septic pumps. (hard wire or single receptacle only)
FAU if located in the garage or located in a FAU utility enclosure within the dwelling. Consult the local inspector. Also, the local inspector may require that the FAU circuit be connected to a Fusetron outlet (single receptacle) with an Edison base fuse.
The local inspector may exempt other appliances or areas. Example: some AHJs exempt smoke detectors and paddle fans.
Manufacturer’s requirements have top priority. If installation instructions say no AFCI or GFCI, local inspector must comply.
AFCI PROHIBITED

There are also circuits that are prohibited from having AFCI protection: Fire sprinkler system alarm which shall be energized from the service panel with metallic conduit to a metallic box. (No AFCI or GFCI protection.)
Home security systems that are monitored off site. These systems usually are smoke and burglar alarm combined. The control panel must be energized with a separate circuit with a single receptacle. Local inspector will determine if metallic conduit to a metallic box is required. (No AFCI or GFCI protection.)
Snow and ice melting equipment should have Ground Fault Equipment Protection (GFEP) and shall not have AFCI Protection or GFCI protection.

 

[romex jockey]

They can fine you all they want, you still have to comply with code before they will clear your permit, issue COA, etc. Failure to correct deficiencies can even result in ordering POCO to disconnect the service in many places.

Some inspectors may even feel the same way you do but still must enforce the code.

Kwired, i can barely get the state to do their job as it is here.

many stories, places occupied that they condemned years ago

or never saw a licensed spark, plumber or gas man for that matter

I've been a certified IAEI member of my state's chapter now for over 20 yrs, i've said a few things about the state backin' licensure up

They could change things, but have no motivation to do so, meanwhile we're loosing more licenses than we create, to reciprocation, not retirement

To survive as an EC, is to have to make decisions you see me making in this thread, it's not comfortable.....

~RJ~

 

[romex jockey]

Go ahead, argue it.

The EM switch , according to fire marshals (not nfpa70) needs to be outside, not inside the furnace rm

~RJ~

 

[romex jockey]

So lemme quess....the longer a circuit is, or more load , or both.....the more this effect exists?

~RJ~

 

[mbrooke]

Longer the circuit the more likely a switch or relay breaking load will trip it.