TL; DR: dina underpaneler är allvarligt inkopplade. Fixing det kommer att kräva löpande ledningar, eftersom den sista installatören troligtvis var en idiot
Vi startar resan i NEC 215.6:
215.6 Feeder Equipment Grounding Conductor. Where a feeder supplies branch circuits in which equipment grounding conductors are required, the feeder shall include or provide an equipment grounding conductor in accordance with the provisions of 250.134, to which the equipment grounding conductors of the branch circuits shall be connected. Where the feeder supplies a separate building or structure, the requirements of 250.32(B) shall apply.
Eftersom alla dina paneler är i samma struktur, är 250.32 (B) irrelevant (och så är matarens längd - NEC bryr sig inte om hur länge en matare är försedd med spänningsfallet inom gränserna) , så vi går vidare till 250.134:
250.134 Equipment Fastened in Place or Connected by Permanent Wiring Methods (Fixed) - Grounding. Unless grounded by connection to the grounded circuit conductor as permitted by 250.32, 250.140, and 250.142, non-current-carrying metal parts of equipment, raceways, and other enclosures, if grounded, shall be connected to an equipment grounding conductor by one of the methods specified in 250.134(A) or (B).
(A) Equipment Grounding Conductor Types. By connecting to any of the equipment grounding conductors permitted by 250.118.
(B) With Circuit Conductors. By connecting to an equipment grounding conductor contained within the same raceway, cable, or otherwise run with the circuit conductors.
Exception No. 1: As provided in 250.130(C), the equipment grounding conductor shall be permitted to be run separately from the circuit conductors.
Vi ignorerar återigen referensen till 250.32, men nu finns det flera problem till hands. Först är 250.140 också irrelevant, eftersom det endast handlar om elektriska spår och torktumlare, inte matare. Medan 250.142 (B) ser lovande ut,
(B) Load-Side Equipment. Except as permitted in 250.30(A)(l) and 250.32(B) Exception, a grounded circuit conductor shall not be used for grounding non- current-carrying metal parts of equipment on the load side of the service disconnecting means or on the load side of a separately derived system disconnecting means or the overcurrent devices for a separately derived system not having a main disconnecting means.
Exception No.1: The frames of ranges, wall-mounted ovens, counter-mounted cooking units, and clothes dryers under the conditions permitted for existing installations by 250.140 shall be permitted to be connected to the grounded circuit conductor.
Exception No.2: It shall be permissible to ground meter enclosures by connection to the grounded circuit conductor on the load side of the service disconnect where all of the following conditions apply:
(1) No service ground-fault protection is installed.
(2) All meter enclosures are located immediately adjacent to the service disconnecting means.
(3) The size of the grounded circuit conductor is not smaller than the size specified in Table 250.122 for equipment grounding conductors.
Exception No.3: Direct-current systems shall be permitted to be grounded on the load side of the disconnecting means or overcurrent device in accordance with 250.164.
Exception No.4: Electrode-type boilers operating at over 1000 volts shall be grounded as required in 490.72(E)(1) and 490.74.
Inget av undantagen till det gäller alls för din situation, och hänvisningen till 250.32 (B) undantag är också, igen, irrelevant. Dessutom är 250,30 (A) (1) oanvändbar eftersom den endast handlar med separata härledda system (t.ex. en generator) och inte till nätverksnätet.
Detta lämnar oss med 250.130 (C):
(C) Nongrounding Receptacle Replacement or Branch Circuit Extensions. The equipment grounding conductor of a grounding-type receptacle or a branch- circuit extension shall be permitted to be connected to any of the following:
(1) Any accessible point on the grounding electrode system as described in 250.50
(2) Any accessible point on the grounding electrode conductor
(3) The equipment grounding terminal bar within the enclosure where the branch circuit for the receptacle or branch circuit originates
(4) An equipment grounding conductor that is part of another branch circuit that originates from the enclosure where the branch circuit for the receptacle or branch circuit originates
(5) For grounded systems, the grounded service conductor within the service equipment enclosure
(6) For ungrounded systems, the grounding terminal bar within the service equipment enclosure
Tyvärr för dig är punkt 5 här inte ett godkännande för att göra vad som gjordes i ditt hus, bara möjligheten att köra en ny jordledning tillbaka till den neutrala samlingsskenan i din servicepanel. Så måste du springa jordledningar tillbaka från underpanelerna till en punkt som är bunden till jordnätet, separera sedan neutral och jordad på alla underpaneler.
När det gäller Longnecks oro för brutna jordledningar, kan det vara koden (det beror på hur din AHJ tolkar 250.130 (C)) medan det går att använda en enda jordtråd. Det finns två mycket bättre alternativ: