'sparks' when connecting gas pipe to furnace

[MTW]

But unfortunately no egc from em-cum-service equipment!

There is no requirement for a separate EGC from, the emergency disconnect to the main service panel, the neutral serves that purpose when you bond the neutral bus to the ground bus at the main service panel, with the main overcurrent device.

The circuit conductors between the emergency disconnect and the main service disconnect are treated as service entrance conductors
and the establishment of a separate ground bus only occurs after the main service overcurrent device.
Only after that main service overcurrent device, do the neutral and the grounding system conductors become separate and isolated from each other.

The emergency disconnect would also have a bond connection between the neutral bus and the enclosure ground bus, to serve the purpose of handling ground fault currents in the emergency disconnect, If it lacks a factory neutral to ground connection.

 

[WD40]

After reviewing the code on EM disconnects I advised the customer that I am not the code expert but I suspect this installation is illegal, for three reasons:
#1 the meter / main is labeled suitable for use only as service equipment making it ineligible sa a Em disconnect under 230.85(B)(3)
#2 the main breaker in the basement SQ-D panel is not 'nearest the point of entrance of the service conductors' as the SE cable travels thru a crawlspace and basement over 20' before it hits the panel a violation of 230.70(A)(1)
#3 The Grounding Electrode conductors and bonding conductors are bonded the the neutral at different points, connecting the CSST gas pipe to neutral EM disconnect and the ground bar at the service panel caused objectionable current 250.6 on the CSST. I suspect if nothing else changed but the #6 was moved from the EM disconnect to the main service panel the ground loop on the CSST would go away.