Need code referance ?

[hurk27]

Re: Need code referance ?

For single circuits or a multiwire circuit one or more single pole switch's are allowed as the disconnect as long as it is rated for the circuit, and it disconnects all ungrounded conductors that enter the building.
Keep I'm mind that for the purpose of this a multiwire circuit can be considered a single circuit as said in 225.30

225.36 Suitable for Service Equipment.
The disconnecting means specified in 225.31 shall be suitable for use as service equipment.
Exception: For garages and outbuildings on residential property, a snap switch or a set of 3-way or 4-way snap switches shall be permitted as the disconnecting means.

[ October 28, 2005, 10:01 PM: Message edited by: hurk27 ]

 

[Jhr]

Re: Need code referance ?

Monday I will be changing out the garage panel so as I can allow for a 60 amp main breaker OUCH!

 

[haskindm]

Re: Need code referance ?

If you are using the cold water line as the grounding electrode, you will need to have, or install, a "supplemental grounding electrode". See 250.53(C)(2).

 

[jwelectric]

Re: Need code referance ?

Originally posted by haskindm:
If you are using the cold water line as the grounding electrode, you will need to have, or install, a "supplemental grounding electrode". See 250.53(C)(2).

I understand why you made this comment but I will have to respectfully disagree.

250.32 Buildings or Structures Supplied by Feeder(s) or Branch Circuit(s).
(A) Grounding Electrode. Building(s) or structure(s) supplied by feeder(s) or branch circuit(s) shall have a grounding electrode or grounding electrode system installed in accordance with 250.50. The grounding electrode conductor(s) shall be connected in accordance with 250.32(B) or (C). Where there is no existing grounding electrode, the grounding electrode(s) required in 250.50 shall be installed.

In 250.32 it states that the grounding electrode is to be installed according to 250.50

250.50 Grounding Electrode System.
All grounding electrodes as described in 250.52(A)(1) through (A)(6) that are present at each building or structure served shall be bonded together to form the grounding electrode system. Where none of these grounding electrodes exist, one or more of the grounding electrodes specified in 250.52(A)(4) through (A)(7) shall be installed and used.

250.52 Grounding Electrodes.
(A) Electrodes Permitted for Grounding.
(1) Metal Underground Water Pipe. A metal underground water pipe in direct contact with the earth for 3.0 m (10 ft) or more (including any metal well casing effectively bonded to the pipe) and electrically continuous (or made electrically continuous by bonding around insulating joints or insulating pipe) to the points of connection of the grounding electrode conductor and the bonding conductors. Interior metal water piping located more than 1.52 m (5 ft) from the point of entrance to the building shall not be used as a part of the grounding electrode system or as a conductor to interconnect electrodes that are part of the grounding electrode system.

As outlined in 250.50 the grounding electrodes outlined in 250.52 are be bonded together as one.
The statement was made that the water pipe will be used for the grounding electrode so as required I reference 250.50 which refers to 250.52 only. No where in these two sections does it require me to comply with 250.53.

I have submitted a proposal to correct this by having 250.32 to refer to part III of 250 instead of the way it is worded now.



[ October 31, 2005, 10:14 AM: Message edited by: jwelectric ]

 

[Jhr]

Re: Need code referance ?

Now the NEC allows me to bond to the cold water in the garage, and it is what my inspector wants, now he also mentioned that if a lighting bolt hit the garage that would be the reason for the bonding, which to me sounds corny :roll: because what good is the bonding to the cold water going to do in this situation, if a bolt of lighting hits the garage it will hit the highest part of the roof would it not, then you either have a big hole in the roof and or fire . Grounding is the most misunderstood thing in the electrical trade

 

[haskindm]

Re: Need code referance ?

JWElectric,
The change of wording that you are proposing is exactly the way it was worded in the 2002 Edition. I don't know why it was changed, it is certainly less clear now, but I don't believe the general meaning has been altered. I would like to see the wording revert back to the way it was.
We agree that a grounding electrode is required in the instance. We agree that the electrode must comply with 250.50. 250.50 refers us to 250.52 which defines the electrode that meet the requirements of 250.50. 250.53 then explains HOW the electrodes defined in 250.52 MUST be installed. This states that a metal underground pipe MUST "be supplemented by an additional electrode...." There is nothing in 250.32 that indicates that this section does not apply. 250.50 tells us that a grounding electrode system is required.
250.52 tells us what grounding electrodes may make up that system.
250.53 tells us how to install the electrodes that make up the system. These sections must be evaluated together. We cannot pick and choose between them.

 

[haskindm]

Re: Need code referance ?

jhr,
Bonding the water pipes in the garage has nothing to do with lightning (using the waterline as a grounding electrode does, but you say you are bonding it). We bond the pipe in order to clear a fault in the event that the piping becomes energized. Otherwise the pipe would remain energized until something that provides a path back to the grounding system come into contact with it completing the circuit. Hopefully this "conductor" is not a person.

 

[Jhr]

Re: Need code referance ?

Bonding the water pipes in the garage has nothing to do with lightning (using the waterline as a grounding electrode does, but you say you are bonding it).

Ok bad choice of words , I will be using the cold water line as my GEC at the garage, but now explain to me how the lightning bolt would travel thru the roofing shingles, wood studs etc to the cold water line and gets disipated into the earth. Like I've stated before on other posts, I've seen plenty of lightning strikes, and never has a cold waterline or ground rod been efective at disipating the lightning bolt, I will tell you this I've seen the effects that a lightning strike has on a cold waterline, and it wasn't pretty .

 

[haskindm]

Re: Need code referance ?

There is not much that will protect a structure in the event of a direct lightning strike. What you are dealing with is the "fall of potential" from a nearby strike. By referencing your electrical system to ground you are ensuring that the electrical system ground is at the same potential as the earth at the location of the structure. Lightning protection is as much art as science, but experience has shown that it is beneficial to have your electrical ground at earth potential and that is the purpose of a grounding electrode.
Bottom line a grounding electrode is required at the building unless it is fed by "only a single circuit". The question is "how does lightning know not to strike near a building that is served by only one circuit"????!!!!

[ October 31, 2005, 02:25 PM: Message edited by: haskindm ]

 

[George Stolz]

Re: Need code referance ?

Originally posted by Jhr:
Like I've stated before on other posts, I've seen plenty of lightning strikes, and never has a cold waterline or ground rod been efective at disipating the lightning bolt, I will tell you this I've seen the effects that a lightning strike has on a cold waterline, and it wasn't pretty

 

[mvannevel]

Re: Need code referance ?

Originally posted by charlie b:

This garage has only one feeder. So the "not more than six" rule in 225.32(A) does not apply.

I'm not really sure where you're coming from on this. 225.33(A) in the '02 code says that the disconnecting means for each supply permitted in 225.30 shall consist of not more than six switches. So, whether or not the structure has one feeder or additional feeders as permitted in 225.30, the requirement for six swipes of the hand would still apply. The fact that Jhr has 8 breakers installed in his panel means he exceeds these six swipes of the hand and a single disconnecting means is required for that panel. I do agree with your statement that it needn't be a main breaker, but could be an un-fused disconnect or pull-out.

[ November 01, 2005, 09:46 AM: Message edited by: mvannevel ]

 

[allenwayne]

Re: Need code referance ?

Severak weeks ago I brought this up but the life of me didn`t print it nor can I find it.
Basically I have a seperate guest quarters on my property that is about 200 ft from the main panel.Some years ago someone burried 3 # 2`s from main to seperate structure,that is a 2 br 1 bath guest quarters for friends ,inlaws,or anyone that wants to come stay here for a few days.Last month I renovated the kitchen,gas stove ,builtin over stove micro,40 gal w/h,The load is general lidgting and a bath gfci.and a 2-1/2 ton package unit with a 5 kw heat strip min is 20 ma bkr 30 amp
Originally the panel was on the inside of an exterier wall. Easy swap reroute underground to the now 3r exterior ,panel an exterior 12x12x6 pvc j box for the existing circuits.2 in nipple into new panel so far so good.Problem being there is no egc or gec at all.
I am getting ready to add a 12 X 12 metal shed on the rear along side the 3r panel,for a washer and dryer and storage.My intention is to install 2 ground rods being this is sugarsand from the exterior panel along side the new shed.Since this is in essense going to be a seperate structure with a 30 amp dryer circuit and a washer circuit and probably 1 maybe 2 circits inside I for lighting and gfci receptacles and a dedicated 20 amp compresssor circuit ?
My concern is this.I have poured footer with rebar within the footer I left a # 4 bare attached to a 20 ft, piece of # 5 rebar in the footer.The actual floor wil be 2 x 12pt with t & g osb as a floor.I don`t want to bring this footer bond of this seperate stuctutre into the panel causing a prallel course for a ground ( This is a high lightining strike area.)
Am i correct in assuming that as long as i hit the ground rod with a seperate connection from the footer in the shed and bond to the ground rod I am compliant in all aspects.Also being that it is in essence a seperate structures will I need an exterior means of disconect for the guest quarters and also the seperate shed.?
To answer the next question this is a permit install,but regardless I do want to be code compliant 100 %
Too add a seperate ground from the original house panel to the guest quarterspanel is not an option,just want he best remedy to an already screwy situation.Any thoughts guys ???I know that if there was an isolated 4wire system then grounds and neutrals would have to be seperated,It`s just that the 3 wire feed has me a bit confused

 

[charlie b]

Re: Need code referance ?

Originally posted by mvannevel: The fact that Jhr has 8 breakers installed in his panel means he exceeds these six swipes of the hand and a single disconnecting means is required for that panel.

I was focused on the original question of whether this panel needs to have a main breaker. My intent was to say that it does not, but that a main breaker is probably the best way to go. The alternative is to use a single disconnect outside or inside.

You said it more clearly, and I agree with the way you said it.

 

[mvannevel]

Re: Need code referance ?

Thanks charlie, I understand what you were getting at now.

 

[Jhr]

Re: Need code referance ?

Well George just look at the post that THE GREATNESS of ROGER put up, look where the lightning strikes are shown, do you think the weatherhead or the panel will hold up with no damage, because a GEC system was present, much less a ground rod, there would be severe damage to both items, I belive the big miconseption, is that lightning will be disipated thru the GEC system with no damage to either item, I also belive a picture like the one in Rogers post is misleading, and I wish I could remember under what topic, there was a post in the archives which I looked thru before signing on that said something to the effect of and I qoute " so we all agree ground rods are for lightning protection" end qoute, lighting stikes is why we have lightning protection systems but that is a field I know litle about. If there is such system present then both the GEC system and the lightning protection system shall be bonded together. But like I said before grounding is the most misunderstood subject in our trade.

[ November 01, 2005, 04:13 PM: Message edited by: Jhr ]