Circa Telecom

Area Of Inquiry:

General Inquiries	Module Questions	Grounding & Bonding
Terminal (BET) Help	Installation Support

Can unshielded cable be spliced to the outgoing shielded stubs on our protectors?	How do I know if I have a good ground?
Is it acceptable to daisy chain the ground connections when using more than one Circa protector?	Do we need to ground both ends of a cable or conduit? Won't that cause a ground loop?
What gauge of ground wire is acceptable?	If there is no ground present, how do I install a protector? Can I use a water pipe?

Can unshielded cable be spliced to the outgoing shielded stubs on our protectors?
Unshielded cable may be spliced to outgoing cable stubs, but may only be used on the protected side of the terminal. Additionally, only shielded OSP cable may be used outside and incoming stubs MUST be spliced to shielded cable.

Is it acceptable to daisy chain the ground connections when using more than one Circa protector?
No! Every time the ground is daisy chained, the ground performance degrades due to the connection losses. The ideal acceptable way of grounding protectors is to run a separate ground from each protector to the ground system. Alternatively, the first protector can be grounded to the ground system, and then several other protectors can be connected to the first protector's ground bar. This will provide a "star" type grounding arrangement, and is acceptable as well. The extra ground points on the satellite units shall not be used. See the diagram below.

Alternatively, a continuous piece of unshielded ground wire can be run through each of the ground bars of the protectors, and then to the ground point. See the diagram below.

What gauge of ground wire is acceptable?
As per NEC article 800.40, a 14 AWG wire (or greater) is required from each protector to the ground system. A bonding jumper of 6 AWG (or larger) copper or equivalent wire is required to bond the communications ground to the power ground where separate grounds are used. It is acceptable to bond several electrodes together. If more than one protector is being grounded, then a 6 AWG or larger ground wire is required.

How do I know if I have a good ground?
The resistance between the ground system and the protector can be measured with an ohmmeter to check the ground quality. An ideal ground will be 0 Ohms. Typically, a good installation should see less than 1-Ohm resistance, up to a maximum of 25-Ohms.

Do we need to ground both ends of a cable or conduit? Won't that cause a ground loop?
Yes. As per NEC article 800.33, cables and conduits entering a building shall be grounded as close as possible to the point of entrance. Therefore, both ends must be grounded.

Ground loops are caused when the ground potential at either end of a cable is not the same. For example, if the ground at the first end was 0 Volts (ideal), and the second end was 0.5 Volts, then current will naturally flow from the second end to the first end inside the ground cable. In our application, the cable sheath is not used to transmit the phone signal, so this ground loop does not impact the performance of the installation. In applications where the ground is crucial for the operation of the system (I.E. car stereos), then the ground loop will introduce extra noise to the system.

If there is no ground present, how do I install a protector? Can I use a water pipe?
As per NEC article 800.40 (2), if there is no acceptable grounded structure, then a ground rod or pipe not less than 5 feet in length and �" in diameter shall be driven into permanently damp earth. It shall be located at least 6 feet from any other ground electrode. Steam or hot water pipes shall not be used as a ground electrode. It is acceptable to use metallic cold water pipes if there is no other ground path.

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