Minimum crossing/parallel clearance between direct buried cables (33KV power cable) and gas pipeline

OP,
Not too much about it is stated in the Code ( Assume B31.8). Table 4.9 in CSA Z662 specifies a clearance of 300 mm for underground cables and pipeline.
However, you need to be careful about when the pipeline is close to the grounding facilities of electrical transmission line structures, substation, generating stations and other facilities that has high fault current carrying grounding network. Fault current can damage to personnel and pipieline coating and steel.
Where buried pipelines are close to high fault current-carrying grounding networks, remedial measures can be necessary to protect the pipeline from resulting potential gradients in the earth near the pipelines.

GDD
Canada

I suggest you contact the owners of these other facilities to find out what their own requirements are.

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"Is it the only lesson of history that mankind is unteachable?"
--Winston S. Churchill

Who there first? Cable or pipeline?

They get to decide.

But for a crossing 500mm to 750 is reasonable.

Parallel running 5m?

There's no hard and fast numbers here. [pre][/pre]

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