1. Corning Optical Communications
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AEN179, Revision 0 - Page 1 of 5
© 2022 Corning Optical Communications. All rights reserved
Published: 07/25/2022
Handhole Size Considerations
AEN179, Revision 0
Civil costs are a major part of deploying a buried network. Determining the appropriate size
handhole for the installation can reduce capital expenses. For example, a smaller handhole
may fit into a green space better, reduce the need to cut or re-pour concrete, as well as
added material and shipping costs and complexities of larger handholes. Therefore, it is
prudent to assess the minimum handhole sizes for each deployment.
Handhole Layout
When determining how large the handhole needs to be to store the terminal, connectors, and
cable slack, one of the first considerations is how the terminal will be installed. Having an
idea of how you want the handhole organized is needed to understand how you can fit the
items inside of the box. Some customers choose to mount the terminal to the wall of the
handhole, so that it is higher, out of the way of cable slack, and easily accessible (Figure 1,
Option 1). Many choose to simply place the terminals in the bottom of the handhole and
avoid the cost and complexity of bracketry (Figure 1, Option 2). Both methods of storage
are industry accepted.
Figure 1. Terminal installation options
Conduit Placement
Another factor to consider is conduit orientation into the handhole. Traditionally conduits are
swept into the bottom of the handholes at some angle (30-45°). These sweeps force the
cables to come out of the duct at that same angle before transitioning to a horizontal or
vertical loop. When trying to maximize the usable space within the handhole and reduce the
needed size, it is important to consider how this is done. Duct entry into the handhole, along
with the number of ducts entering, should be aligned to the products used within the duct
*not to scale

2. AEN179, Revision 0 - Page 2 of 5
© 2022 Corning Optical Communications. All rights reserved
Published: 07/25/2022
along with the type of handhole used. For instance, when using a narrower and deeper
handhole (flowerpot) it is best to bring the conduit into the bottom vertically. Alternatively,
when working in a rectangular box, bringing the conduit horizontally into the side of the
box as low as possible is better (see Figure 2). Both methods better align with where the
usable storage is in the handhole, how the cable slack will be stored, and reducing the risk
of potential cable damage. Bringing the conduit and cable in along the perimeter versus in
the center generates extra room for cable and/or terminal placement. Verifying the number
of ducts needed and their fitment is critical for handhole selection, as it can overcrowd a
small box quickly or lead to potential cable damage and installation challenges.
Figure 2. Conduit entry
Once the conduit or cable pathway is determined, and the overall layout of the handhole
is understood, one can begin to determine the minimum dimensions needed.
Considerations include the size of the terminal/hardware stored in the handhole and the
cables being used and routed. Also, remember that the handholes are three
dimensional, and effectively using all of the space will allow use of the smallest handhole. An
example of this can be seen in Figure 3.
Calculating Space Needs
First, the dimensions of the terminal need to be known, inclusive of the cable stub attached if
applicable; but most importantly length and width. You also need to know the minimum bend
diameter (MBD) of the cables that are involved. These dimensions are the starting point for
understanding the need. The lid of the box must be large enough to accommodate these
two items. The dimensions for Optisheath®
and Evolv™ terminals are listed below, as an
example.
Figure 3. Handhole Space Utilization

3. AEN179, Revision 0 - Page 3 of 5
© 2022 Corning Optical Communications. All rights
reserved Published: 07/25/2022
Next add in the connector length and cable minimum bend radius (MBR), to the terminal
length, as shown in the equation below.
𝑇𝑜𝑡𝑎𝑙 𝐿𝑒𝑛𝑔𝑡ℎ = 𝑇𝑒𝑟𝑚𝑖𝑛𝑎𝑙 𝐿𝑒𝑛𝑔𝑡ℎ + 𝐶𝑜𝑛𝑛𝑒𝑐𝑡𝑜𝑟 𝑜𝑟 𝑆𝑡𝑢𝑏 𝐵𝑜𝑜𝑡 𝐿𝑒𝑛𝑔𝑡ℎ + 𝐶𝑎𝑏𝑙𝑒 𝑀𝐵𝑅∗
*Could also use MBD or Recommended coil diameter
Figure 4. Total hardware length
This will determine one minimum dimension. Choosing MBR vs MBD in the equation
above also means that the cable slack will need to be stored beside/under the terminal, or in
another location, and not in the same plane as the terminal ports. If storing slack in-line with
the ports of the terminal are critical, using MBD or desired coil diameter is needed. Some
cable coil diameters are listed below.
Cable Minimum Bend
Radius
Minimum Bend
Diameter
ROC™ 2.5" (64 mm) 5" (127mm)
SST 3.2" (82 mm) 6.4" (163mm)
MiniXtend®
3.23" (82 mm) 6.5" (165mm)
Round ROC 2.5" (64 mm) 5" (127mm)
Dual Drop 1.2" (30 mm) 2.4" (60 mm)
Table 2. Cable Bending Dimensions
In the case of a stubless Evolv terminal, Pushlok(TM) connectors, and ROC cable; the Evolv
terminal is 6.06" in length; the mated Pushlok connector is 3.5", and the MBR for ROC is
2.5". Adding these together would tell us that the handhole needs to have a 12" minimum
dimension in one direction. In this example, wanting to store the cable slack in-line with
the ports would take the minimum length from 12" to 16".
Evolv™ Terminal Length Width Depth
1 Port Row 2-4 Port 6.06" (154 mm) 3.29" (84 mm) 1.18" (30 mm)
6-8 Port 6.06" (154 mm) 5.29" (134 mm) 1.18" (30 mm)
12 Port 6.06" (154 mm) 7.5" (190 mm) 1.18" (30 mm)
2 Port Rows 6-8 Port 6.06" (154 mm) 3.29" (84 mm) 2.30" (58 mm)
12-16 Port 6.06" (154 mm) 5.29" (134 mm) 2.30" (58 mm)
Optisheath®
Terminal Length Width Depth
2-4 Port 11.3" (287 mm) 2.9" (73 mm) 2.6" (66 mm)
6-8 Port 12.3" (312 mm) 3.4" (86 mm) 3.0" (76 mm)
12 Port 15.0" (381 mm) 5.8" (147 mm) 4.0" (101 mm)
Table 1. Terminal Size Comparison

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© 2022 Corning Optical Communications. All rights reserved
Published: 07/25/2022
Figure 5. MBR vs MBD
If the terminal stub has a connector on the other end that will be mated inside the same
handhole, such as FlexNAP™, the equation for that length is below. This length does not
need to be combined with the length above if the tails of the terminal provide enough
length to route inside the handhole. This length is critical though, as it is not always
flexible like the cable, and in some cases can be longer than the terminal length calculated
above.
𝑇𝑜𝑡𝑎𝑙 𝐶𝑜𝑛𝑛𝑒𝑐𝑡𝑜𝑟 𝐿𝑒𝑛𝑔𝑡ℎ = 𝑀𝑎𝑡𝑒𝑑 𝐶𝑜𝑛𝑛𝑒𝑐𝑡𝑜𝑟 𝐿𝑒𝑛𝑔𝑡ℎ + 𝐶𝑎𝑏𝑙𝑒 1 𝑀𝐵𝑅 + 𝐶𝑎𝑏𝑙𝑒 2 𝑀𝐵𝑅
Figure 6. Total Connector Length
If it is desired to mount the terminal inside the handhole, with or without a bracket, the length
requirements mentioned above must be determined in conjunction with the box's shape.
Using the numbers from above, an Evolv™ terminal with drops mated needs to have
12" of continuous length, in any dimension. This indicates that a rectangular
handhole will need one side that can accommodate that length along the flat side, without
getting into the corners. A good example of a handhole that would work in this scenario is
a 10"x15"x12". The 15" long side provides enough room to mount the terminal and bracket
to the wall with room for the cables to be routed down into the bottom of the
handhole. Figure 7 illustrates the space needed for an Evolv terminal compared to an
Optisheath® terminal.

5. AEN179, Revision 0 - Page 5 of 5
© 2022 Corning Optical Communications. All rights reserved
Published: 07/25/2022
Figure 7. Terminal envelope
In the case where the terminal and cable slack are not mounted to the wall, the space can be
used more creatively. The space needed to fit everything could be accommodated by
placing the terminal at an angle within the handhole. Below are some
conservative handhole sizes that can accommodate being used with the
Evolv™ terminals and drop products. Using the space more efficiently could
allow for smaller packaging and handholes. As mentioned above, the
rectangular handholes tend to provide better options when multiple ducts are
entering and exiting the space, where the cylindrical handholes work well at
customer premises and places where the cables are direct buried on exit.
Lid Shape Length Width Depth
Rectangle 15" 10" 12"
Square 11" 11" 16"
Round - 12" 18"
Table 3. Evolv Handhole Examples
Multi-Use Handholes
Often handholes need to be used for more than one function. Some of the handholes may
strictly house terminals, and some drop slack. These typically allow the use of something
smaller. There may be other handholes that need to accommodate multiple items, such as
larger cables or splice enclosures. In these cases the same formulas and considerations
apply. Bringing the conduit into the base of the handhole in a horizontal plane allows the
cable to easily transition into a vertical or horizontal coil. The splice enclosure could be
mounted to the wall of the vault or left lying in the bottom. Either way, the length of the
closure plus the bend radius of the cables entering need to be considered to determine the
minimum length needed in the handhole. Once that is understood, adding in the envelope
needed to store a terminal and drop slack will determine if a larger handhole is needed, or if
the existing vault is sufficient. Contact your Corning representative if you would like to
discuss more options and how the products can work in your network.