Electrician Talk banner
1 - 18 of 18 Posts

·
Banned
Joined
·
1,246 Posts
I'm replacing an existing panel. He can tell me a lot of things, but his code ref is 220, kind of vague.

408.30 General. All panelboards shall have a rating not
less than the minimum feeder capacity required for the load
calculated in accordance with Part III, IV, or V of Article
220, as applicable.



Maybe he just meant to use 220 for the load calc?
 

·
Electrical Simpleton
Joined
·
3,350 Posts
I'm replacing an existing panel. He can tell me a lot of things, but his code ref is 220, kind of vague.
If it's a 1 for 1 swap with no increase in load I don't see the reason for the load calc nor what purpose it would serve.

Pete
 

·
Registered
Electrician
Joined
·
4,465 Posts
Inspector is requiring it quotes article 220, that's all just 220. Also is requiring second ground rod even with a metal underground water pipe in place.
unfortunately the new rules '11' require two ground rods for anything over 100a:mad:
Even with the water pipe?
Yes, unless you can prove that the single rod is at 25 ohms or less.

Pete
@ Pete,
I believe you are wrong about this.
Here is what the "11" code says:
250.53 Grounding Electrode System
Installation
Informational Note: See 547.9 and 547.10 for special
grounding and bonding requirements for agricultural buildings.
(A) Rod, Pipe, and Plate Electrodes. Rod, pipe, and plate
electrodes shall meet the requirements of 250.53(A)(1)
through (A)(3).
(1) Below Permanent Moisture Level. If practicable, rod,
pipe, and plate electrodes shall be embedded below permanent
moisture level. Rod, pipe, and plate electrodes shall be
free from nonconductive coatings such as paint or enamel.
(2) Supplemental Electrode Required. A single rod, pipe,
or plate electrode shall be supplemented by an additional
electrode of a type specified in 250.52(A)(2) through (A)(8).

The supplemental electrode shall be permitted to be bonded
to one of the following:
(1) Rod, pipe, or plate electrode
(2) Grounding electrode conductor
(3) Grounded service-entrance conductor
(4) Nonflexible grounded service raceway
(5) Any grounded service enclosure
Exception: If a single rod, pipe, or plate grounding electrode
has a resistance to earth of 25 ohms or less, the supplemental
electrode shall not be required.
#2 (above in red) says that if you have a single rod it has to be supplemented by a type specified by 250.52(A)(2)-(A)(8)
(A)(1) says:

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 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 conductor(s) or jumper(s), if installed.
So if he has either a rod or the water pipe as the main electrode and has, in addition, either a rod or water pipe, then he has the supplemental electrode and 2 rods isn't required in addition to the water pipe. Only need one rod and one supplemental.
 

·
Registered
Joined
·
2,923 Posts
@ Pete,
I believe you are wrong about this.
Here is what the "11" code says:
#2 (above in red) says that if you have a single rod it has to be supplemented by a type specified by 250.52(A)(2)-(A)(8)
(A)(1) says:

So if he has either a rod or the water pipe as the main electrode and has, in addition, either a rod or water pipe, then he has the supplemental electrode and 2 rods isn't required in addition to the water pipe. Only need one rod and one supplemental.
Pete isn't wrong.

First is 250.50...

250.50 Grounding Electrode System. All grounding electrodes
as described in 250.52(A)(1) through (A)(7) 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)(8) shall be installed and used
So, if there is metal water coming to the building, you have to use it.

Now that you have used the incoming water, 250.53 D applies...

(2) Supplemental Electrode Required. A metal underground
water pipe shall be supplemented by an additional
electrode of a type specified in 250.52(A)(2) through
(A)(8). If the supplemental electrode is of the rod, pipe, or
plate type, it shall comply with 250.53(A).
The supplemental
electrode shall be bonded to one of the following:

(1) Grounding electrode conductor
(2) Grounded service-entrance conductor
(3) Nonflexible grounded service raceway
(4) Any grounded service enclosure
(5) As provided by 250.32(B)


Next is 250.53 A 2...

(2) Supplemental Electrode Required. A single rod, pipe,
or plate electrode shall be supplemented by an additional
electrode of a type specified in 250.52(A)(2) through
(A)(8)
. The supplemental electrode shall be permitted to be
bonded to one of the following:

(1) Rod, pipe, or plate electrode
(2) Grounding electrode conductor
(3) Grounded service-entrance conductor
(4) Nonflexible grounded service raceway
(5) Any grounded service enclosure

Exception: If a single rod, pipe, or plate grounding electrode
has a resistance to earth of 25 ohms or less, the
supplemental electrode shall not be required
Metal underground piping is not within A2-A8, so you would have to choose a different supplemental electrode. Most go with the second rod.

If there is building steel you could eliminate the rods all together, but to prove 250.52 A (1 and 2) on an existing building would be difficult.
 

·
Registered
Electrician
Joined
·
4,465 Posts
Pete isn't wrong.

First is 250.50...

So, if there is metal water coming to the building, you have to use it.

Now that you have used the incoming water, 250.53 D applies...





Next is 250.53 A 2...



Metal underground piping is not within A2-A8, so you would have to choose a different supplemental electrode. Most go with the second rod.

If there is building steel you could eliminate the rods all together, but to prove 250.52 A (1 and 2) on an existing building would be difficult.
I stand corrected!:(

Didn't notice that the required list started with (A)(2). Just saw that it said to use one from the list. Then, of course, the water pipe had to be the first one on the list, which is (A)(1) :cry:
 
1 - 18 of 18 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top