As the code guy around here, I've been asked if it is compliant to install some 12 AWG supply-side taps, that is ahead of the service disconnect, for energy management meters. Let's say it's a 2000A switchboard. Is this complaint with the NEC?
Supply-side connection on switchboard for an EMS
- Thread starter jes25
- Start date
- Occupation
- Licensed Electrician
I've seen taps off a main lug with small wire in manufactured/listed things like transfer switches or control panels. I don't know of a code sanctioned way to do it in the field. I might know a guy who has hooked up some meters and surge protectors that way when it wasn't being inspected.
DBill64
Member
- Location
- Washington, USA
- Occupation
- I&E Technician
Tap being made upstream of the service disconnect? Then tap rules don't apply since it's not on a feeder. 12AWG would be fine to use. I'm pretty sure it would also be fine to do if it was a feeder tap less than 10ft and the tap conductor doesn't leave the switchboard (it would of course have to end up landing at an OCPD rated at 20A or less).
The only other thing I would be careful about would be potentially voiding that wonderful UL listing with any modifications. May have to get a field listing after the work is complete depending on what is being done.
The only other thing I would be careful about would be potentially voiding that wonderful UL listing with any modifications. May have to get a field listing after the work is complete depending on what is being done.
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DBill64
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- Location
- Washington, USA
- Occupation
- I&E Technician
Also of note: the only thing that references service taps is Article 230.46 (2023 Edition)
230.46 Spliced and Tapped Conductors.
Service-entrance conductors shall be permitted to be spliced or tapped in accordance with 110.14, 300.5(E), 300.13, and 300.15. Power distribution blocks, pressure connectors, and devices for splices and taps shall be listed. Power distribution blocks installed on service conductors shall be marked “suitable for use on the line side of the service equipment” or equivalent.
Pressure connectors and devices for splices and taps installed on service conductors shall be marked “suitable for use on the line side of the service equipment” or equivalent.
So other than making sure the devices used to make the tap are listed for use on service conductors, there really isn't much else in the way of code about service taps.
230.46 Spliced and Tapped Conductors.
Service-entrance conductors shall be permitted to be spliced or tapped in accordance with 110.14, 300.5(E), 300.13, and 300.15. Power distribution blocks, pressure connectors, and devices for splices and taps shall be listed. Power distribution blocks installed on service conductors shall be marked “suitable for use on the line side of the service equipment” or equivalent.
Pressure connectors and devices for splices and taps installed on service conductors shall be marked “suitable for use on the line side of the service equipment” or equivalent.
So other than making sure the devices used to make the tap are listed for use on service conductors, there really isn't much else in the way of code about service taps.
The way I'm thinking about it is that if I we could tap the line side of the bus without voiding the listing, we could install another separate service disconnect just for the meters.
DBill64
Member
- Location
- Washington, USA
- Occupation
- I&E Technician
Yah, that'd work. Would be best to do the tap in a separate enclosure upstream of the switchgear probably (but in the same space). Something like this drawing perhaps? Just have to make sure to use devices that are rated for service use.
