200 amp service

[Paelectrician]

Do I use the 6awg ground to both water and ground rods

 

[raider1]

Re: 200 amp service

Nope, for the water pipe you need to use a #4 for a 200 amp service based on a 4/0 aluminum service entrance conductors from Table 310.15(B)(6) and using Table 250.66.

The GEC or bonding jumper run to the ground rod is not required to be larger than #6 based on 250.66(A).

Chris

 

[Paelectrician]

Re: 200 amp service

Nope, for the water pipe you need to use a #4 for a 200 amp service based on a 4/0 aluminum service entrance conductors from Table 310.15(B)(6) and using Table 250.66.The GEC or bonding jumper run to the ground rod is not required to be larger than #6 based on 250.66(A).

Chris

Thank you Sir

 

[peach]

Re: 200 amp service

Why, or why don't designers and contractors get the concept that the EGC is not the same as the GEC (or that the EGC needs to be upsized if they use aluminum feeders rather than copper)?

 

[480sparky]

Re: 200 amp service

Why, or why don't designers and contractors get the concept that the EGC is not the same as the GEC (or that the EGC needs to be upsized if they use aluminum feeders rather than copper)?

Because they don't have to take a test to go to work.

 

[peach]

Re: 200 amp service

thanks Sparky... it still doesn't help the inspector in the field (who is always the bad guy)... how many times have we seen copper VE'd out in favor of aluminum conductors... with no other consideration given to what the designer has just done to us?

 

[dcspector]

Re: 200 amp service

Back to the original Posters question. One of the reasons the Bonding Conductor must be larger in size Vs The GEC is the bonding conductor must be able to carry a Fault back to source via the neutral at service point to poco as an example. The GEC to lets say a GE as in Ground rod only is there to reduce objectionable currents such as lightning strikes or surges. This was simply a quick explanation of theory and intent.

 

[McClary's Electrical]

Good explanation. I'd just like to add that the reason a #6 can be used to the rods, when it is a GEC, just like the #4, is that due to the resistance of the rods in soil they can only carry XXX amount of current. The #6 can always carry the maximum amount of current that can possibly fllow through a ground rod(s). When the water pipe could possibly seee much higher current flows in certain situations.

 

[Uncle Bob]

On the lighter side,

A famous golfer once said; "If your caught on the golf course during a lightning storm; take your one iron out and hold it straight up over your head. Not even God can hit a one iron." :grin:

Uncle Bob

 

[peach]

you can use a #6 GEC for a 4000 amp service... it's the EGC that needs to be sized based on conductor size... the two serve 2 different purposes..

One is grounding.. one is bonding..

UB... I think it was Lee Trevino who said that..

 

[raider1]

you can use a #6 GEC for a 4000 amp service... it's the EGC that needs to be sized based on conductor size... the two serve 2 different purposes..One is grounding.. one is bonding..

UB... I think it was Lee Trevino who said that..

Actually the equipment grounding conductor is sized based on the overcurrent protective device protecting the circuit conductors.

An equipment bonding jumper on the line side of a service or the main/system bonding jumpers are based on the size of the conductors.

Chris

 

[Span]

I have no problem with T250.66 grounding electrode conductir, but never enforce water main and gas pipe bonding to follow this table.

Old house don't have ufer or rod for grounding, it rely on under ground water pipe as grounding perpose. Currently a lot of pipe wree being

replace by PVC, they're no longer serve as grounding perpose.

span

 

[chris kennedy]

I have no problem with T250.66 grounding electrode conducotir, but never enforce water main and gas pipe bonding to follow this table.

You might want to consider that.

250.104 Bonding of Piping Systems and Exposed Structural Steel.(A) Metal Water Piping. The metal water piping system shall be bonded as required in (A)(1), (A)(2), or (A)(3) of this section. The bonding jumper(s) shall be installed in accordance with 250.64(A), (B), and (E). The points of attachment of the bonding jumper(s) shall be accessible.

(1) General. Metal water piping system(s) installed in or attached to a building or structure shall be bonded to the service equipment enclosure, the grounded conductor at the service, the grounding electrode conductor where of sufficient size, or to the one or more grounding electrodes used. The bonding jumper(s) shall be sized in accordance with Table 250.66 except as permitted in 250.104(A)(2) and (A)(3).

 

[Span]

Chris, very true as your quo on 250.104. Exposed metal frame I'll follow T250.66.

For interior metal pipe such as water pipe and gas pipe I'll ask for#6 bonding, because they serve as any interior metal pipe which might become

energized by contact with electrical wire have a solid grounding path.

span

 

[raider1]

Chris, very true as your quo on 250.104. Exposed metal frame I'll follow T250.66.For interior metal pipe such as water pipe and gas pipe I'll ask for#6 bonding, because they serve as any interior metal pipe which might become

energized by contact with electrical wire have a solid grounding path.

span

You should follow Table 250.66 for the bond to the metal water pipe as well.

Chris

 

[peach]

Actually the equipment grounding conductor is sized based on the overcurrent protective device protecting the circuit conductors.An equipment bonding jumper on the line side of a service or the main/system bonding jumpers are based on the size of the conductors.

Chris

Really? so if they change from copper to aluminum, they can still use a #10 EGC.. if it worked for copper? I don't think that's what the code says.. bigger aluminum (and we see a lot of this value engineering).. carries more potential fault than the copper sized for the same breaker, right?

 

[McClary's Electrical]

Peach, When you look at a certain GEC size in 250. 66 you'll notice that size GEC is listed for (2) different sizes of ungrounded conductors. (1) aluminum and (1) for copper.

 

[raider1]

Really? so if they change from copper to aluminum, they can still use a #10 EGC.. if it worked for copper? I don't think that's what the code says.. bigger aluminum (and we see a lot of this value engineering).. carries more potential fault than the copper sized for the same breaker, right?

Peach, Equipment grounding conductors are sized based on Table 250.122 based on the size of the overcurrent protective device protecting the conductors.

Also bigger aluminum does neccessarily not carry more fault current than copper if they are both size for the same breaker.

Chris

 

[peach]

The NEC I'm looking at (albeit is not a bright shiny new version), goes on to say "Where conductors are adjusted in size to compensate for voltage drop, equipment grounding conductors, where required shall be adjusted proportionately according to circular mil area."

AFter the part where it says "copper, aluminum, or copper-clad aluminum equipment grounding conductors shall not be less than shown in Table 250-95" .. ok.. it's an old code book, so the section number is different.. is the verbiage different too?