Electrical Problems -Narrowing the Cause Category

Narrowing the Cause Category

There are several possible causes for a given symptom.

	S Y M P T O M
CAUSE:	Does not work	Goes off and on at will or flickers	Runs dim or bright sometimes	Won’t go off	Shocks
A. Short/Ground-or-arc-fault/Overload	Yes	--	--	--	--
B. Circuit (or main) wire connection poor ("open")	Yes	Yes partially	Yes	--	--
C. Ground-fault without an intact intended ground path	--	--	--	--	Yes
D. Miswiring	Yes	--	--	Yes	Yes
E. Bad or mis-set device	Yes	Yes	--	Yes	--

Without knowing the kind of cause at work in your problem, you are unlikely to get to the root of it.How does a person go about identifying which one kind of cause is behind the symptom? To answer this, we need to get specific for each symptom, as follows.
1. Does Not Work. Is the cause some kind of short [A], an overload [A], an open [B], a miswiring [D], or a bad device [E]?

1. A bad or turned-off device itself [E] (other than a bad circuit breaker) will not affect more lights or appliances than the device is supposed to control or serve. But there can be connections at that switch, receptacle or light that could be poor and affect the circuit from that point on.
2. A miswiring [D] should almost be assumed if the problem’s timing corresponds with some home remodeling or some Upgrading of devices that has gone on. By miswiring I mean wrongly connected, not poorly connected. When there is a miswiring, it can sometimes be the ultimate cause behind other causes listed in the chart above.
3. When some things aren't working, the most important cause to determine or eliminate is the one I lump under the title "Short/ground-or-arc-fault/overload" [A]. I say this because these all result in a tripped breaker (blown fuse) or tripped GFI. If such trippedness is not discovered early, the cause behind the outage will escape you. In fact, finding and attempting to reset these can quickly lead to knowing which of these three subcauses is operating. Namely, a breaker or GFI that lets itself be reset indicates that there had been an overload or a non-recurring ground-or-arc-fault. (One exception about the breaker that allows resetting is if the breaker sometimes gets hot during normal loads because of poor connections at or in it; this will make it false-trip at times.)... On the other hand, if a resetting results quickly in a retripping, then you have a short or an active ground-or-arc-fault. Because the trippedness of a device is crucial to know, make certain you can confirm or eliminate the matter of tripping, because these devices are often hard to locate, reset, or interpret.
4. An open [B] is most likely the cause of an outage if the other causes above (i., ii., iii.) have been ruled out. But independently, an open neutral is almost certain if hotness is still present at a non-working item. A receptacle tester would read "open neutral" or "hot and ground reversed". An open is also likely if the dead items number more than one, but not enough to constitute a whole circuit. Dead outlets in the Places required to have GFCI protection, should not be thought to have an open till a tripped GFI is ruled out.

2. Goes Off and On At Will or Blinks or Flickers. Is this symptom due to a partial open [B] in the wiring connections, or something wrong with a device [E] or fixture? If the extent of the blink or outage is limited to one item or one switch's set of lights, then the cause is probably a bad device or fixture. If the things affected are more widespread, then the cause will be a connection that is compromised -- partially open -- somewhere. Its location would be one of the Connection points along the circuit, at its breaker, or at a main wire. A main wire problem would affect things on more than one circuit.
3. Runs Dim or Bright Sometimes. This indeed has only one cause-category: an open [B]. It may be intermittent or not. Is a main wire (of power company, meter area, or within the panel) having trouble, or is it a circuit wire? If these strange voltages affect things in many parts of the home, a Main wire connection is probably poor -- often the power company's fault (call them). If it is limited to one or two circuits, then it is probably an Open neutral shared by two circuits.
4. Won’t Go Off. Is this from a bad device [E] or a miswiring [D]? Miswiring from remodeling or from Upgrading of devices should occur to someone right away as a likely cause. Whatever won’t go off will be noticed quickly and associated with such recent activity. Aside from miswirings, the cause will be that the device that is supposed to shut the thing off is either not adjusted right, or else is faulty and will need replacement Repair is usually impossible or iffy.
5. Shocks Someone. Aside from the rare 240-volt shock, this would by nature be a case of a ground-fault finding its only path to ground [C] through a person’s body. Miswiring [D] is a prior cause that might set up this condition. Rewiring or replacement of devices in a home may be fresh in your mind and suggest good places to look.