All electrical equipment must have sufficient clearances as described in NEC 110.26.

The simplest way to think of this is to imagine a phone booth around the equipment:

• There should be NO obstructions within 36" in front of the equipment

• The equipment needs to fit in a clear window on the wall measuring a minimum of 30" by 6'6".

  • Note that under NEC 110.26.(A)(3) Exception 2, existing systems may be grandfathered in if the working clearance height is less than 6'6", however, all new equipment will be required to comply to the full 6'6" height clearance.

EGRESS WINDOWS

For a window to be considered a point of egress, it will need to meet the following criteria:

1. The window is operable, meaning it can be manually opened or closed.

2. The open side of the window must be at least 2' wide.

We are mainly concerned about egress windows on the first level or whichever level is on grade with the electrical equipment. 

• DO NOT PLAN TO MOUNT BELOW ANY POINT OF EGRESS.

This photo shows very clearly that the existing equipment is behind the fence.

This means we need to plan for where the new equipment will go. For most utilities, you need to plan for new AC disconnects and PV meters to be located in front of the fence but as close to the existing equipment as possible.

• This can vary depending on utility. For example, CORE has said to put the new equipment with the old behind the fence before in the past.

  • Designers need to check the utility requirements closely

  • Surveyors need to get photos on either side of the fence in this situation.

This is the final planned layout that was submitted to the utility.

We will get into utility required PV equipment later in the design training.

Looking closely, what are some issues you can spot in this image?

It looks like there might be a sufficient 30" window of clearance that the equipment is mounted in, however, there is one issue that needs to be fixed:

• There is permanent shelving and other temporary items blocking the needed working depth clearance.

• This shelving is the main concern. It appears that it would most likely take more than 30 minutes to relocate.

• These items are also obstructing the needed clearance, but they can simply be shifted over 3' to the left to provide ample clearance.

  • This would take less than 30 minutes.

This shelving may or may not be an issue. From this visual alone, it looks like it could be 30" away from the left edge of the panel, but we would need precise measurements to be sure.

So what should the designer do?

The designer should submit this to Electrical Review due to the permanent shelving obstructing the working depth. Additional notes can be added about shelving that may also be coming close to the working clearance.

Looking closely, what are some issues you can spot in this image?

In this example, we have both an AC unit and a gas meter grouped with the meter. So what are the considerations here?

1. The AC unit is fine as is. It appears to be well over 3' away from the meter providing sufficient clearance.

However,

2. The meter is mounted too close to the gas diaphragm on the gas meter. 

We will need to ensure that there is a mounting area nearby where we can mount the new wall equipment without encroaching on the default clearance around the gas meter.

This example is a little more tricky. There is no doubt there are objects obstructing the required working depth. There's two main questions to ask to figure out if Electrical Review will be required or not.

1. Do the obstructions appear to be permanent?

   • Things like piping, gas meters, sinks, etc. would be considered permanent.

   • Things like shelving, fridges and other appliances can sometimes be moved as a customer obligation.

2. How long would it take to remove the obstruction(s)

   • If it is just clutter, it should always be a customer obligation.

   • With shelving and appliances, if it looks like it would take more than about 30 minutes to correct, it should be flagged for PER Escalation

In this case, it is just clutter and the shelving does not appear to be bolted to the wall. This should be called out as a Customer Obligation.

In this example, we have bushes in front of the meter obstructiong working depth clearance in front of the existing equipment. 

This should be called out as a Customer Obligation.

2020 NEC SERVICE DISCONNECT REQUIREMENTS

The 2020 edition of the NEC introduced some new requirements regarding service disconnects. Not all jurisdictions using the 2020/2023 will require us to upgrade older services but some of them might, so it is important to know the updated code specifics regarding services.

Below are the new articles and updates from the 2020 text.

(2020 NEC) 230.85 Emergency Disconnects:

For one- and two-family dwelling units, all service conductors shall terminate in disconnecting means having a short-circuit current rating equal to or greater than the available fault current, installed in a readily accessible outdoor location. If more than one disconnect is provided, they shall be grouped.

2017 NEC and prior: 

There was previously no requirement for there to be an accessible emergency disconnecting means outdoors. In many older markets such as Virginia, Oregon, South Carolina, etc., you will often see "stand alone" meters, meaning that the main disconnect/MSP is indoors somewhere which was allowed in older versions of the code and may be allowed to be grandfathered in depending on the jurisdiction.

The principle difference is that the 2020 NEC requires an outdoor accessible emergency service disconnect.

(2020 NEC) 230.71(B) Maximum Number of Disconnects: 

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

Essentially, this is saying, we may have up to 6 service disconnects. Service disconnects are main disconnects that are located between a power source (utility, PV, Customer owned generator, etc.) and loads being serviced by this source (typical branch circuits like lights, laundry, appliances, etc. that are attached to load side branch breakers.)

2017 NEC and prior: 

A residence was still only allowed up to 6 service disconnects, however, it used to be allowed to have all 6 service disconnects in a single enclosure.

The principle difference is that the 2020 NEC requires each service disconnect to be in a separate enclosure with only one main service disconnect per enclosure.

230.67 Surge Protection:

(A) Surge-Protective Device. All services supplying dwelling units shall be provided with a surge-protective device (SPD).

(B) Location. The SPD shall be an integral part of the service equipment or shall be located immediately adjacent thereto.

Exception: The SPD shall not be required to be located in the service equipment as required in (B) if located at each next level distribution equipment downstream toward the load.

(C) Type. The SPD shall be a Type 1 or Type 2 SPD.

(D) Replacement. Where service equipment is replaced, all of the requirements of this section shall apply.

2017 NEC and prior: This is another service requirement that did not exist prior to the 2020 NEC.

The principle difference is that the 2020 NEC requires each service to be equipped with an SPD.

408.36 Overcurrent Protection:

In addition to the requirement of 408.30, a panelboard shall be protected by an overcurrent protective device having a rating not greater than that of the panelboard. This overcurrent protective device shall be located within or at any point on the supply side of the panelboard.

(D) Back-Fed Devices

Plug-in-type overcurrent protection devices or plug-in type main lug assemblies that are backfed and used to terminate field-installed ungrounded supply conductors shall be secured in place by an additional fastener that requires other than a pull to release the device from the mounting means on the panel.

EATON BR

For BR type breakers, this will usually be a retaining screw. 

Note that it is considered a code violation and/or equipment damage for holes to be drilled in other types of breakers to suit a retaining screw. 

• This should mainly be seen on BR type breakers with some older discontinued brands such as Challenger or Westinghouse

CUTLER-HAMMER

For CH type breakers, you will often see either a white or red tab indicating the mechanical retaining attachment.

SIEMENS

For Siemens type breakers, you will often see either a white or red tab indicating the mechanical retaining attachment.

• This is more subtle because some times it may be a small gray clip as seen in the photo on the right.

SQUARE D HOM

There are a few different types of retaining kits used with HOM type breakers. Most often it is some type of metal bracket.

• make sure you can see the attachment to the enclosure.

SQUARE D QO

There are a few different types of retaining kits used with QO type breakers as well. Most often it is some type of metal bracket or a plastic bracket as seen to the right.

• make sure you can see the attachment to the enclosure.

Every space on this bus accepts tandems according to the labelling.

UPSIDE DOWN BREAKERS

• Refers to breakers that are installed such that when the breaker is in the “on” position, the handle faces down.

• This needs to be corrected prior to installation.

There are several breakers in this example that are upside down. 

• One of the service disconnects is upside down.

• Three breakers on the lower bus are upside down.

Labels can also tell us the NEMA rating of the equipment. NEMA rating is an alphanumeric rating system used to designate the weather resistance of an enclosure.

• Watch out for NEMA type 1 and 2 equipment outdoors: these are only approved for interior use.

Based on this label, can this load center be mounted outdoors?

• Yes, a rating of 3 and above designates equipment as resistant to outdoor conditions.

Based on this label, can this load center be mounted outdoors?

• No, type 1 & 2 are indoor only.

Based on this label, can this load center be mounted outdoors?

• No, this is type 1.

Based on this label, can this load center be mounted outdoors?

• No, this is type 1.

There is also a distinction between MSP wiring and Sub Panel wiring that needs to be noted. 

• Ground and neutral should never be bonded (connected) in any sub panel enclosure. 

• This means that sub panels will require both a neutral and a ground wire connecting to the MSP. 

• It will also mean that grounds and neutrals for each branching circuit need to be on separate terminal bars.

  • You shouldn't see green/bare wires and white/gray wires on the same terminal bar in ANY sub panel.

The example on the right shows a typical ground bar on a sub panel. Notice, there are only wires that are either bare or with green sheathing on this terminal bar. The visible white wires are terminating on a separate insulated neutral bar not visible in this photo, but present just under the breakers.

When should ground and neutral be bonded?

• Only at the main service disconnect.

• Ground and neutral are bonded either by landing on the same terminal bar or by forming a connection between ground and neutral bar through other means such as a green screw bonding the insulated neutral bar to the enclosure.

  • This means that in the MSP You CAN have green/bare wires and white/gray wires on the same terminal bar.

The example on the right shows a fairly common ground/neutral terminal bar as seen in an MSP enclosure. Notice that both bare AND white wires terminate on this bar. 

It is completely acceptable for ground wires to be double lugged with wires of the same size. The example to the right would not warrant any additional work or corrections of any kind.

While it is acceptable to double land grounds in the same terminal, this is not the case with neutrals

Neutrals should never be double landed like this. 

The designer needs to instruct the installer to get these neutrals on their own terminal by either relocated to another terminal lug on the existing neutral bar or by installing a new insulated neutral bar terminal if there are no available spots.

The main thing to be on the lookout for is undersized service conductors and feeders.

• These conductors are sized to handle a specific current rating. 

• Most often, you won't be able to read the wire labeling to determine the size of the wire, so you will need to use your better judgement.

This is an example of undersized wire in a 200A disconnect. 

• For context, these are aluminum wires which would need to be sized at 4/0 AWG to handle 200A.

  • The minimum would be 2/0 AWG if the conductors were copper.

Refer to the chart above as a loose guide. These conductors appear to be no larger than 2 AWG Al. This is severely undersized.

Flag for PER if you see this.

This example is the same load center. Look closely to see if you notice any other issues.

This branch breaker is rated for 100A. The rating indicates that it is likely servicing a sub panel elsewhere in the home. These wires look suspicious.

• The minimum AL conductor rated for 100A would be 2 AWG.

• The conductors plugged into the 50A 2P breaker on the other side of the bus look closer to 2 AWG than the sub panel feeders do.

Flag for PER Escalation if you see this.

BANJO METERS

Banjo meters are identified by a meter base that is abnormally small, usually only occupying the total size and area of the meter bulb. Also look for:

• abnormally small service risers

or

• no riser at all, only SE-R cable going to the service drop.

Flag for PER Escalation if you see this in any area outside of Oregon.

Max overhead span over the roof is 48”.

These service cables are spanning completely over the other side of the roof.

This should be flagged for PER Escalation

These service cables are only about 8 inches off of the roof. The minimum clearance over the roof is 18" with the minimum service drop height being 24"

This should be flagged for PER Escalation.