250.64(B)

[jimatwork]

I have to ground a PDU(150kva trans.) on a raised computer floor.I was running emt then changing over to LFMC(sealtight)with grounding hubs at each end as required.My question is can a grounding electrode conductor be installed in LFMC? 250.64 (B)only lists RMC,IMC,RNC,EMT or cable armor. I can't find the definition of cable armor.

Thanks

 

[benaround]

Re: 250.64(B)

jimatwork,

250.64(B) It does state 'otherwise it SHALL be in rmc,imc,--etc.

LFMC is not on the list.

I have not seen cable armor for a long time now,but it looks like mini mc type armor with a bare copper,solid GEC inside of it.

frank

 

[redfish]

Re: 250.64(B)

Original question by jimatwork,

Can a grounding electrode conductor be installed in LFMC?

</font>

• <font size="2" face="Verdana, Helvetica, sans-serif">If you are just grounding your transformer look at 350.60 in the 2002 Code and that will take you in the right direction. Same article in the 2005 Code,however there is a slight change. Where flexibility is not required, LFMC shall be permitted to be used as an equipment grounding conductor when installed in accordance with 250.102</font>

<font size="2" face="Verdana, Helvetica, sans-serif">

 

[benaround]

Re: 250.64(B)

redfish,

350.60 has absolutly no value concerning jimatwork's question.

If your just grounding the transformer,then you are installing a GEC.

frank

 

[redfish]

Re: 250.64(B)

If one were installing a GEC, Then I would agree with benaround. However if one were to need only to ground ones equipment using emt and then xing over to LFMC I would read 350.60 carefully. What do you think benaround?

[ July 06, 2005, 09:08 PM: Message edited by: redfish ]

 

[redfish]

Re: 250.64(B)

jimatwork, are you talking about an equipment ground?

[ July 06, 2005, 10:43 PM: Message edited by: redfish ]

 

[hurk27]

Re: 250.64(B)

If the transformer is a separately derived system then it needs to meet the requirements in 250.30,
Which I believe will require an GEC.