Just wanted to wish you all a Happy New Year, and remind you that the 2020 NEC is now in effect. All permits pulled prior to 12/31/23 are still going to use the 2017 NEC.
NEW TO THE 2020 NEC IS ARTICLE 242 WHICH COMBINES OLD ARTICLES 280 AND 285. THIS ARTICLE SHOULD MAE IT EASIER TO UNDERSTAND THE REQUIREMENTS FOR SURGER ARRESTERS AND SURGE-PROTECTIVE DEVICES.
Till next time be safe work safe
Jake
New to the 2020 NEC is section 230.85 which will require a disconnect outside a one or two family dwelling unit. Again this starts December 31st 2023
Till next time
Be safe work safe
Jake
The six service disconnect rule for services is retained in the 2020 edition of the NEC, but is revised with the change that for up to six service disconnects they would require each disconnecting means to be installed in separate enclosures or separate compartments. We will no longer will be able to have a meter main combo with two 200 amperes mains fed off of a 400 ampere meter if they enclosed in a single enclosure. See the changed Code section below.
The mains below in the picture are enclosed in separate enclosures within the piece of switchgear.
230.71(B) Two to Six Service Disconnecting Means.
Two to six service disconnects shall be permitted for each service permitted by 230.2 or for each set of service-entrance conductors permitted by 230.40, Exception No. 1, 3, 4, or 5. The two to six service disconnecting means shall be permitted to consist of a combination of any of the following:
(1) Separate enclosures with a main service disconnecting means in each enclosure
(2) Panelboards with a main service disconnecting means in each panelboard enclosure
(3) Switchboard(s) where there is only one service disconnect in each separate vertical section where there are barriers separating each vertical section
(4) Service disconnects in switchgear or metering centers where each disconnect is located in a separate compartment
Informational Note No. 1: Metering centers are addressed in UL 67, Standard for Panelboards.
Informational Note No. 2: Examples of separate enclosures with a main service disconnecting means in each enclosure include but are not limited to motor control centers, fused disconnects, circuit breaker enclosures, and transfer switches that are suitable for use as service equipment.
Till next time be safe work safe
Jake
New to the 2020 is Surge–Protection for dwelling units services. This section 230.67 gives us the parameters for the location and type of surge protection to be provided.
A new section was added to service equipment for barriers.
230.62(C) Barriers.
Barriers shall be placed in service equipment such that no uninsulated, ungrounded service busbar or service terminal is exposed to inadvertent contact by persons or maintenance equipment while servicing load terminations.
If disconnecting or de-energizing the service conductors supplying a service panelboard, switchboard, or switchgear is not feasible, it might be necessary for a qualified person to work on that equipment with the load terminals de-energized but with the service bus still energized. Barriers provide physical separation (adequate distance or an obstacle) between load terminals and the service busbars and terminals. This provides some measure of safety against inadvertent contact with line-energized parts during maintenance and installation of new feeders or branch circuits.
Can’t see the whole picture just Click on it.
Till next time be safe work safe.
Jake
Text taken from the enhanced Code Book 2020 NFPA 70.
Thanks goes out to Tommy for the great picture of a generator hookup, among other things.
Till next time be safe work safe.
Jake
New to the 2020 NEC is a section on “line side splices or taps”. Devices used to make splices or taps on the line side of the service disconnect shall now be listed for use on the line side of the main (service side). Section call for effective date of 1/1/23, but will not actually go into effect until 12/31/23 when adopted by the Florida Building Code.
Can’t see the whole picture just click on it.
Till next time be safe work safe.
Jake
This section is often mis-understood when making the measurement or just understanding the requirements of the section to meet the requirements for outlet spacing in a residential home. I hear people says walls 1’ (12’”) or more need outlets, but that is for countertops in kitchen and similar work surfaces covered in section 210.52(C)(1). In the picture below we have several French doors separated by wall space less than 2’ in width. This section does not require us to install outlets in these wall areas. As stated in the section walls less 2’ (24”) or more need to have receptacle outlets installed. If the space is less than 24” then outlets need not be installed.
210.52(A)(2)(1) Wall Space.
As used in this section, a wall space shall include the following:
(1) Any space 600 mm (2 ft) or more in width (including space measured around corners) and unbroken along the floor line by doorways and similar openings, fireplaces, and fixed cabinets that do not have countertops or similar work surfaces
Till next time be safe work safe.
Jake
New in the 2020 Code book is an adjusted “General Lighting Load Table “ for most types of occupancies except for dwelling units. The lighting loads have been changed to new “VALUES” based on how much lower the wattage is for new LED lighting being installed. The table shown below is just a sample of the table and not the complete one. The values are drastically reduced and include the 125% for continuous load factors. Just as the Table states it covers all occupancies except dwelling units, dwelling units will be covered in section 220.14(J), which is also new to the Code book. You will find the the general lighting loads are a lot smaller now for non-dwelling load calculations which will reduce the size of the lighting loads to large buildings, which will lend help with other new loads that we are seeing such as car chargers. There are several notes that go with the table to explain which lighting loads go with which type of occupancy. In the table the far righthand column is the VA per square foot number that we will use figure the general lighting load.
Note: The 125 percent multiplier for a continuous load as specified in 210.20(A) is included when using the unit loads in this table for calculating the minimum lighting load for a specified occupancy.
a Armories and auditoriums are considered gymnasium-type occupancies.
b Lodge rooms are similar to hotels and motels.
c Industrial commercial loft buildings are considered manufacturing-type occupancies.
d Banks are office-type occupancies.
e Garages — commercial (storage) are considered parking garage occupancies.
f Clubs are considered restaurant occupancies.
g Barber shops and beauty parlors are considered retail occupancies.
h Stores are considered retail occupancies.
Till next time be safe work safe
Jake
Sizing of Service and/or Feeder Conductors for a dwelling unit PER SECTION 310.15(B)(7) see Example D7 in ANNEX D in the back of the Code book.
Service conductors and feeders for certain dwellings are permitted to be sized in accordance with 310.15(B)(7).
If a 200-ampere service is required, to select the service conductor size is as follows:
200 amperes (the size of required main) × 0.83 = 166 amperes per 310.15(B)(7). (THIS IS THE 83% RULE)
If no other adjustments or corrections are required for the installation, then, in accordance with Table 310.15(B)(16), a 2/0 AWG Cu which is good for 175 amperes or a 4/0 AWG Al which is good for 180 amperes will meet this rating at 75°C (167°F).
The following is the section from the 2017 Code book.
310.15(B)(7) Single-Phase Dwelling Services and Feeders.
For one-family dwellings and the individual dwelling units of two-family and multifamily dwellings, service and feeder conductors supplied by a single-phase, 120/240-volt system shall be permitted to be sized in accordance with 310.15(B)(7)(1) through (4).
As you can see this section it is for “one and two family dwellings, and multifamily dwellings”that use 120/240 voltages for services and/or feeders. In this section a reduced neutral is allowed.
For one-family dwellings and the individual dwelling units of two-family and multifamily dwellings, single-phase feeder conductors consisting of 2 ungrounded conductors and the neutral conductor from a 208Y/120 volt system shall be permitted to be sized in accordance with 310.15(B)(7)(1) through (3).
In this section we can use it for the same types of units, but the voltage is 208Y/120 and a reduced neutral “can not be used”. So you will be required to pull the same size neutral under this section. Here in South Florida this voltage is used in Multifamily buildings.
(1) For a service rated 100 through 400 amperes, the service conductors supplying the entire load associated with a one-family dwelling, or the service conductors supplying the entire load associated with an individual dwelling unit in a two-family or multifamily dwelling, shall be permitted to have an ampacity not less than 83 percent of the service rating.
(2) For a feeder rated 100 through 400 amperes, the feeder conductors supplying the entire load associated with a one-family dwelling, or the feeder conductors supplying the entire load associated with an individual dwelling unit in a two-family or multifamily dwelling, shall be permitted to have an ampacity not less than 83 percent of the feeder rating.
(3) In no case shall a feeder for an individual dwelling unit be required to have an ampacity greater than that specified in 310.15(B)(7)(1) or (2).
(4) Grounded conductors shall be permitted to be sized smaller than the ungrounded conductors, if the requirements of 220.61 and 230.42 for service conductors or the requirements of 215.2 and 220.61 for feeder conductors are met.
The table below comes from ANNEX D in the back of the 2017 CODE book.
This table was made using the 83% rule for sizing the conductors to a residential dwelling unit.
Coming in the 2020 Code Book this Table will have a home at 310.12 which will be nice to see it back in the Code book where it belongs. The inclusion of the 83% rule confused many people and was mis-interpreted all the time. I was often asked if it was 83% of the load calculation, 83% of the wire size and a number of other mis-understood interpretations.
One of the most important parts of this 83% rule is that the load calculation can exceed the ampacity of the conductors chosen.
An example is a 200a load calculation comes out to 190 amperes. We are allowed to use the 83% rule because it is a residential service or feeder. The 200 ampere service rating is multiplied by the 83% ( 200 X 83% = 166. amperes) which gives us 166 amperes. We then go to Table 310.15(B)(16) and go down the 75 degree column and find the a 2/0 copper conductor has the ampacity of 175 amperes which exceeds the 166 ampere used in the 83% rule, so a 2/0 Cu. can be used for a 200 ampere service or feeder.
Hope this helps.
Till next time be safe work safe.
Jake
