ing alongside power cable 39. Sensor lines 43, 45 may be 4O electrical wires  conveying power to  sensors  in instrument subs 23, 33 and transmitting electrical signals from  the sensors. Alternately, sensor lines 43, 45 may comprise fiber optic lines that transmit light signals from fiber optic sensors

in instrument  subs 23,  33. 43

Sensor line 43 sealingly passes through a sensor line port 46 formed in the wall of lower instrument sub 23. Similarly, sensor line 45 passes through a sensor line port 46 in the wall of upper instrument sub 33. Each sensor line port 46 is preferably  spaced  180 degrees from motor lead 35.

Referring to FIG. 2, upper instrument sub 33 has a cylindrical housing 47 with a bore 49 that is coaxial with a longitudinal axis 53 of ESP 17 (FIG. 1). The following description of upper instrument sub 33 as shown in FIGS. 2 and 3 is also applicable to lower instrument sub 23, which may be identical. A rotatable drive shaft 51 is centered on axis 53 within bore 49 and is part of a shaft assembly extending upward from motor 19 (FIG. 1) for driving primary pump 27. In FIG. 2, the outer diameter of  housing

47 is concentric with axis 53 and also is of a larger diameter 60

than the outer diameters of seal section 21 and pump 27. Preferably, the outer diameter of instrument sub housing 47 is the same as the outer diameter of motor 19. The minimum inner diameter  of bore  49 may  be the  same as the    inner

diameter  of  the  housing  for  primary  pump  27  and  seal 65

section 21. The increase in outer diameter creates a greater wall thickness for instrument sub housing 47 than the   wall

greater wall thickness accommodates sensor line port  46.

One reason for primary pump 27 and seal section 21 having a smaller outer diameter than motor 19 is to provide for the passage alongside of motor lead 35. Often the difference in diameter between motor 19 and the inner diameter of cased well 11 is quite small. If primary pump 27 and seal section 21 had diameters equal to motor 19, there may not be enough room for motor lead 35 to be located alongside. Motor lead 35 does not extend alongside motor 19, thus motor 19 may have a larger diameter than pump 27 and seal section 21.

A longitudinally extending groove or recess 55 is formed in the exterior of upper instrument sub housing 47 to receive motor lead 35. Motor lead groove 55 has a depth approxi- mately the same as the thickness of motor lead 35. Alter- nately, a flat could be formed in place of groove 55. Motor lead groove 55 is located 180 degrees from sensor line port

46. The radial distance r1 from axis 53 to the base of motor lead groove 55 is less than the radial distance r2 from axis 53 to the exterior of instrument sub housing 47 at a point 180 degrees from motor lead groove 55. The larger distance r2 results in a greater wall thickness of housing 47 adjacent sensor line port 46 than would occur if housing 47 with its concentric bore 49 had the same outer diameter as primary pump 27. Housing 47 is much shorter than primary pump 27, thus making a greater wall thickness more feasible than if applied to primary pump 27.

As shown in FIG. 2, motor lead 35 has at least one and normally three insulated power conductors 57 extending side-by-side parallel to each other. An outer armor 59 formed of a metal strip may wrap helically around the three conductors 57. Alternately, the three conductors 57 could be located in separate metal tubes. Lower sensor line 43 could be located within armor 59 or on the   exterior.

FIG. 3 illustrates an alternate embodiment of upper instru- ment sub 33' to FIG. 2 in that the outer diameter of instrument sub housing 47' need not be larger than the outer diameters of primary pump 27 and seal section 21. In this embodiment, bore 49' is concentric with axis 53. However, the exterior of housing 47' is eccentric relative to axis 53, resulting in an outer diameter that is eccentric to bore 49' The wall thickness of housing 47' gradually increases from one side to another. This embodiment does not have a motor lead groove, such as groove 55 (FIG. 2) for motor lead 35. Rather, motor lead 35 extends alongside and may touch the exterior of housing 47' at a point of minimum thickness. Sensor line port 46' is located in an area of maximum wall thickness 180 degrees from motor lead 35. The radial distance r1 from axis 53 to the point on the exterior of housing 47' at its maximum thickness is less than the radial distance r2 from axis 53 to the point on the exterior of housing 47' at its maximum thickness. In this embodiment, it is not necessary for the exterior of housing 47' to be cylindrical.