最近到一家新公司上班，培训时有这样一个实际的电气问题的案例。

nnren

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  [. \( g  W0 U8 f7 [Subject: Real Electrical Fire Example
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Basic facts of the case: *
---Electrician received a work order to inverstigate why hall way lights wre not working in an underground pedestrican tunnel between two buildings
---Electrician went alone to investigate an electrical panel in a mechanical room where he thought the breakers were located. Note: the mechanical room is located in the same underground pedestrian hallway.
---Electrician entered the room and when he opened the panel door, observed a series of breakers that were open in tripped position.
---Electrician assumed since the breakers were in the same general area, they controlled the hallway lights.
; V* k  C* z& T! K+ s& Z2 N2 S3 }. D---When the electrician closed the breakers, they immediately tripped again.
---The electrician again closed the breakers and this time they stayed closed.
, i* m7 O5 Y2 q% G$ P* Z# f---The electrician left the mechanical room to investigate whether the lights had come on or not.
6 y/ w( |7 K) r4 b4 X' Y---The hall lights had not come on , so the electrician assumed there was another electrical panel for the hall lights, and went to maintenance to find a print.
---Sometimes later, as a security guard was passing the door that led to the mechanical room, the observed smoke coming from the electrical box and immediately called for an emergency.
---The underground pedestrian hallway was located above one of the office buildings, and therefore the entire office building had to be evacuated because of the fire and smoke.
9 @$ L3 H: n: ~) j3 f! `---The local fire department was called and fire was extinguished.
) O" W5 A$ k9 m7 k: T" I---Damage was confined to the mechanical room.
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Additional Information---Mechanical room contained steam lines, chilled water pumps, and electrical panels
---Room was kept under lock and key
( p" [. K' E8 y' a7 o---The electrical panel did not have circuit breaker labels.

Discuss: --- What went wrong with this assignment?
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答案等有些回应再贴吧。

一点

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nice and waiting.....

lastman

至少得派2人去吧

PCOSI

I would begin with checking the moisture condition and then, examine the panel, especially around the neutral bar, and then test the insulation with megger between the hot wires after those breakers which tripped before and the neutral or neutral bar.

AASTAR

1，SUPERVISOR 不合格；
2，ELECTRICIAN SHOULD IMMEDIATELY REPORT WHAT HE FOUND BEFORE HE TAKE ANY ACTION;

AASTAR

在此提醒大家，如果你不知道或不确定，没有把握，一定要立刻报告LEADHAND或FOREMAN。这不仅是操作规范，也是最大限度保护自己。

nnren

1# nnren
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谢谢各位热心的回复，下面是从材料摘下来的答案：
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What went wrong with this assignment?
1. Supervisor did not discuss the assignment with the electrician.
) m# P' X, G6 K. F3 z2. The electrician made assumptions about the breakers.
3. The electrician did not follow the basics of electrical circuits, that if tey trip when you reset, there must be a problem.
# K/ G: I+ K# L+ j) |6 U4. The electrician should have gone back to the panel once her realized the breakers did not service the hall lights, and checked the breakers.
& |) Z3 U0 p. [) A8 [* j5. Others?
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个人认为最重要的是第三，四点， After reset breaker once and it trips again, never try to reset second times. There must be some issue in this circuit.
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1 u3 D, q* O! T! u; LHopefully, this question can be helpful. Thanks

AASTAR

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同样第二点非常重要，当你不知道的时候，什么都不能做。这还是低压，中高牙呢。。
对自己对别人都是非常危险的。

zhsj

panel do not have good maintenance，breaker who triped have fire must have short circuit. so the discuss 3 is the key problem.