Plans to reschedule a meeting at Newbury after two horses died there at the weekend, are due to be announced later.
Fenix Two and Marching Song fell to the ground and died just before they were to be mounted by their jockeys.
The distressing tragedy happened on the far side of the parade ring and was witnessed by punters.
Kid Cassidy and The Merry Giant were also affected.
Electricity board officials have confirmed that a section of cable has been removed from the course for further examination.
Stuart Hogarth, operations director for Southern Electric Power Distribution, said: "Our initial on-site investigations confirm there was no danger to the public."
Stephen Higgins, joint managing director of Newbury racecourse, said: "We have been reassured that the site is safe and we hope that the final results of this investigation will be established as soon as possible."
Talks were on-going about whether the card, which was due to feature several important trials for next month's Cheltenham Festival, could be saved.
Speaking on his Twitter page, British Horseracing Authority (BHA) head of communications Paul Struthers said no announcement on post-mortem results or rescheduling of the meeting would be made until today.
Rumours of horses suffering burn marks were rife on course, but Struthers added: "Just to be clear re @NewburyRaces not one vet, trainer or jockey mentioned anything about burn marks in, b4 or after official enquiry."
BHA chief executive Nic Coward had told BBC Radio Five Live: "This was a tragic incident and our thoughts have to be with the connections.
"It is premature to describe in detail what happened because that would be speculation, but fingers are being pointed at some kind of electrical fault. Post-mortems are also being carried out."
