Fusing a lamp post from an A/C disconnect (residential)

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Re: Fusing a lamp post from an A/C disconnect (residential)

originally posted by jimwalker:
Anyone willing to admit to using a bulb in place of a fuse while trouble shooting a short in one of them old old srew in fuse panels .
Yes, about a month ago. I thought everyone used this trick. :roll:
 
Re: Fusing a lamp post from an A/C disconnect (residential)

Originally posted by electricman2:
originally posted by jimwalker:
Anyone willing to admit to using a bulb in place of a fuse while trouble shooting a short in one of them old old srew in fuse panels .
Yes, about a month ago. I thought everyone used this trick. :roll:
Click to expand...
Ok, I'll bite.
What does screwing a bulb into a fuse socket accomplish?
:confused:
Dave
 
Re: Fusing a lamp post from an A/C disconnect (residential)

Dave, do you mean why does the light come on if there's a load or a short? :D
 
Re: Fusing a lamp post from an A/C disconnect (residential)

Originally posted by physis:
Dave, do you mean why does the light come on if there's a load or a short? :D
Click to expand...
No, I understand the bulb will light up but what does that tell me that hasn't already been established by the fuse blowing in the first place.
Not trying to be sarcastic, I just don't get it.
I don't see how it would help with trouble shooting or finding the short.
If a new fuse is installed and blows immediately, there is either an overload or a ground fault. If I screw in a light bulb instead and it lights...there could still be either and overload or a fault.

Seriously, am I missing something?

Dave
 
Re: Fusing a lamp post from an A/C disconnect (residential)

Originally posted by davedottcom:
Seriously, am I missing something?
Click to expand...
Yes. The next step: locating the short.

On the presumption that the circuit worked at one time, and the short is possibly intermittent and not visually obvious, it helps to have someone monitor the bulb while the technician wiggles and probes the various outlets on the circuit in question.

It helps to use a bulb because it doesn't require replacing several times while troubleshooting, and it acts as a current-limiter so there is no equipment damage suffered while tracking down (and especially finding) the offending problem.

This is not limited to plug-fuse panels, by the way. You can also temporarily place a rubber socket with a bulb in series with the circuit breaker to do the same kind of troubleshooting. All you need is a single wirenut for the "load side" of the socket.

[ August 25, 2005, 12:14 AM: Message edited by: LarryFine ]
 
Re: Fusing a lamp post from an A/C disconnect (residential)

(Oops! I hit "quote" instead of "edit" again!)

[ August 25, 2005, 12:13 AM: Message edited by: LarryFine ]
 
Re: Fusing a lamp post from an A/C disconnect (residential)

Oh yea, the original question!
Changing the disconnect to a small panel is the way to go.

Dave
 
Re: Fusing a lamp post from an A/C disconnect (residential)

Who needs the helper? Just screw in one of those adaptors and plug in a radio!
:eek:

[ August 25, 2005, 08:45 AM: Message edited by: davedottcom ]
 
Re: Fusing a lamp post from an A/C disconnect (residential)

dillon3c,

Good catch Mr. dillon3c,Glad someone is paying attention.

240.10 sup.fuse can't replace branch circuit.

210.63 GFCI on load side of disconnect.I read right by that one,had my mind on the 'tap'.

240.21{b)(1) I'm going to disagree with you on this one,I feel the 'tap' conductor stops at the OCPD,after that it is just a circuit IMO.

Anyway good job you did for the OP to get the answer he needed.

frank
 
Re: Fusing a lamp post from an A/C disconnect (residential)

Originally posted by benaround:
dillon3c,

240.21{b)(1) I'm going to disagree with you on this one,I feel the 'tap' conductor stops at the OCPD,after that it is just a circuit IMO.

frank
Click to expand...
Morning Frank,
*and thank you for the kind words..

But I guess I need help, getting my mind around this thinking..

IMO..Tap conductor consist after the point of, in statement in 210.63 location,and tapping feeder conductor at line-side of disconnecting means for A/C feeder.

*And at that point the conductors via, to this GFCI receptacle device,to "line-side of the local A/C disconnecting means, are in fact the "tap-conductors",themselves..

IMO,I beleive this intent is for serviceing factor of the A/C equipment alone,and not the intent of "permanently powering" (*hardwiring) other equipment from the load-side of this GFCI receptacle device.(and exceeding ten foot)

*We do agree this is, "a-tapp situation"..

*And it doesn't fit any of the criteria of 210.19(a)(4)

IMO, thus 240.21(b)(1)

*any thoughts..
 
Re: Fusing a lamp post from an A/C disconnect (residential)

Originally posted by dillon3c:
And at that point the conductors via, to this GFCI receptacle device,to "line-side of the local A/C disconnecting means, are in fact the "tap-conductors",themselves..
Click to expand...
I'm a little fuzzy what you're saying.

NEC-2002 240 Definitions. Tap Conductors. As used in this article, a tap conductor is defined as a conductor, other than a service conductor, that has overcurrent protection ahead of its point of supply that
exceeds the value permitted for similar conductors that are protected as described elsewhere in 240.4.
Click to expand...
The little conductor between the lug protected at 30 or 40 amps, and the fuse protected at 5 amps, is the only tap conductor.

It's the only conductor not protected according to conventional OCPD's. It's a tiny wire with only a 30 or 40 amp breaker protecting it. After the fuse, there are no more tap conductors.

I could have sworn those things were called "inline fuse holders." That'll teach me, I guess! :eek:

Aren't HVAC equipment supposed to be on their own dedicated circuit? :confused:
 
Re: Fusing a lamp post from an A/C disconnect (residential)

Morning George, i'm sitting in a room @ the Sheraton @ Virginia Beach ,Virginia trying to type this over Web-T.V.,so bear with me... The tap-conductors are the smaller conductors as you have stated,,"tapped from the A/C feeder conductor"..Location of tap,@"LINE_SIDE"of locall outside disconnecting means @ the A/C equipment. Notice of NEC'05 210.63 "shall be" installed @ an accessible location "for the SERVICING of the A/C EQUIPMENT.--the recepticle outlet "shall not" be connected to the "load side" of the equipment disconnecting means..(meaning tap-permitted) .... Refering to 210.19(4)(c) Quote: other than receptacles.. The in-line fuse holder,,violation of 240.10 Supplemntary overcurrent Protection..

Tap Conductor.@ 240..21 (b)(1) ten-foot tap rule. As far as the overcurrent protection of the smaller tap-conductor (the smaller wire)..Take notice of 240.21(b)(4) Quote: For field installations where the tap-conductors leave the inclosure or valt in which the tap is made,,the ratingof the overcurrent device on the line side (AKA. a/c feeder breaker @ panel where feeder recieves supply)-shall not exceed 10 (ten) times the ampacity of the Tap-conductors-(aka.-the smaller wire as you have said)

George,therein lyes the overcurrent protection for the receptacle device for the "servicing factor" alone of the A/C equipment as I have stated.
*this whole installation in original post,...Violation,non-conforming.. (tuff-typing this on web-tv..,not recommended) later...dillon.. .
 
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